Merge branch 'upstream-nghttp2' into update-nghttp2

# By nghttp2 upstream
* upstream-nghttp2:
  nghttp2 2022-09-21 (87fef4ab)

26 files changed, 3250 insertions, 694 deletions

diff --git a/Utilities/cmnghttp2/lib/includes/nghttp2/nghttp2.h b/Utilities/cmnghttp2/lib/includes/nghttp2/nghttp2.h
index e3aeb9fed3..61a14d99eb 100644
--- a/Utilities/cmnghttp2/lib/includes/nghttp2/nghttp2.h
+++ b/Utilities/cmnghttp2/lib/includes/nghttp2/nghttp2.h
@@ -229,6 +229,13 @@ typedef struct {
 #define NGHTTP2_CLIENT_MAGIC_LEN 24
 
 /**
+ * @macro
+ *
+ * The default max number of settings per SETTINGS frame
+ */
+#define NGHTTP2_DEFAULT_MAX_SETTINGS 32
+
+/**
  * @enum
  *
  * Error codes used in this library.  The code range is [-999, -500],
@@ -399,12 +406,17 @@ typedef enum {
    */
   NGHTTP2_ERR_SETTINGS_EXPECTED = -536,
   /**
-   * The errors < :enum:`NGHTTP2_ERR_FATAL` mean that the library is
-   * under unexpected condition and processing was terminated (e.g.,
-   * out of memory).  If application receives this error code, it must
-   * stop using that :type:`nghttp2_session` object and only allowed
-   * operation for that object is deallocate it using
-   * `nghttp2_session_del()`.
+   * When a local endpoint receives too many settings entries
+   * in a single SETTINGS frame.
+   */
+  NGHTTP2_ERR_TOO_MANY_SETTINGS = -537,
+  /**
+   * The errors < :enum:`nghttp2_error.NGHTTP2_ERR_FATAL` mean that
+   * the library is under unexpected condition and processing was
+   * terminated (e.g., out of memory).  If application receives this
+   * error code, it must stop using that :type:`nghttp2_session`
+   * object and only allowed operation for that object is deallocate
+   * it using `nghttp2_session_del()`.
    */
   NGHTTP2_ERR_FATAL = -900,
   /**
@@ -533,9 +545,9 @@ typedef struct {
    * :type:`nghttp2_on_frame_send_callback`, and
    * :type:`nghttp2_on_frame_not_send_callback`), it may not be
    * NULL-terminated if header field is passed from application with
-   * the flag :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME`).  When application
-   * is constructing this struct, |name| is not required to be
-   * NULL-terminated.
+   * the flag :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`).
+   * When application is constructing this struct, |name| is not
+   * required to be NULL-terminated.
    */
   uint8_t *name;
   /**
@@ -546,9 +558,9 @@ typedef struct {
    * :type:`nghttp2_on_frame_send_callback`, and
    * :type:`nghttp2_on_frame_not_send_callback`), it may not be
    * NULL-terminated if header field is passed from application with
-   * the flag :enum:`NGHTTP2_NV_FLAG_NO_COPY_VALUE`).  When
-   * application is constructing this struct, |value| is not required
-   * to be NULL-terminated.
+   * the flag :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE`).
+   * When application is constructing this struct, |value| is not
+   * required to be NULL-terminated.
    */
   uint8_t *value;
   /**
@@ -622,7 +634,11 @@ typedef enum {
    * The ORIGIN frame, which is defined by `RFC 8336
    * <https://tools.ietf.org/html/rfc8336>`_.
    */
-  NGHTTP2_ORIGIN = 0x0c
+  NGHTTP2_ORIGIN = 0x0c,
+  /**
+   * The PRIORITY_UPDATE frame, which is defined by :rfc:`9218`.
+   */
+  NGHTTP2_PRIORITY_UPDATE = 0x10
 } nghttp2_frame_type;
 
 /**
@@ -691,7 +707,11 @@ typedef enum {
    * SETTINGS_ENABLE_CONNECT_PROTOCOL
    * (`RFC 8441 <https://tools.ietf.org/html/rfc8441>`_)
    */
-  NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL = 0x08
+  NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL = 0x08,
+  /**
+   * SETTINGS_NO_RFC7540_PRIORITIES (:rfc:`9218`)
+   */
+  NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES = 0x09
 } nghttp2_settings_id;
 /* Note: If we add SETTINGS, update the capacity of
    NGHTTP2_INBOUND_NUM_IV as well */
@@ -705,8 +725,8 @@ typedef enum {
  *
  * Default maximum number of incoming concurrent streams.  Use
  * `nghttp2_submit_settings()` with
- * :enum:`NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS` to change the
- * maximum number of incoming concurrent streams.
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS`
+ * to change the maximum number of incoming concurrent streams.
  *
  * .. note::
  *
@@ -860,38 +880,41 @@ typedef enum {
  * The implementation of this function must read at most |length|
  * bytes of data from |source| (or possibly other places) and store
  * them in |buf| and return number of data stored in |buf|.  If EOF is
- * reached, set :enum:`NGHTTP2_DATA_FLAG_EOF` flag in |*data_flags|.
+ * reached, set :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_EOF` flag
+ * in |*data_flags|.
  *
  * Sometime it is desirable to avoid copying data into |buf| and let
  * application to send data directly.  To achieve this, set
- * :enum:`NGHTTP2_DATA_FLAG_NO_COPY` to |*data_flags| (and possibly
- * other flags, just like when we do copy), and return the number of
- * bytes to send without copying data into |buf|.  The library, seeing
- * :enum:`NGHTTP2_DATA_FLAG_NO_COPY`, will invoke
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_COPY` to
+ * |*data_flags| (and possibly other flags, just like when we do
+ * copy), and return the number of bytes to send without copying data
+ * into |buf|.  The library, seeing
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_COPY`, will invoke
  * :type:`nghttp2_send_data_callback`.  The application must send
  * complete DATA frame in that callback.
  *
  * If this callback is set by `nghttp2_submit_request()`,
  * `nghttp2_submit_response()` or `nghttp2_submit_headers()` and
  * `nghttp2_submit_data()` with flag parameter
- * :enum:`NGHTTP2_FLAG_END_STREAM` set, and
- * :enum:`NGHTTP2_DATA_FLAG_EOF` flag is set to |*data_flags|, DATA
- * frame will have END_STREAM flag set.  Usually, this is expected
- * behaviour and all are fine.  One exception is send trailer fields.
- * You cannot send trailer fields after sending frame with END_STREAM
- * set.  To avoid this problem, one can set
- * :enum:`NGHTTP2_DATA_FLAG_NO_END_STREAM` along with
- * :enum:`NGHTTP2_DATA_FLAG_EOF` to signal the library not to set
- * END_STREAM in DATA frame.  Then application can use
- * `nghttp2_submit_trailer()` to send trailer fields.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM` set, and
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_EOF` flag is set to
+ * |*data_flags|, DATA frame will have END_STREAM flag set.  Usually,
+ * this is expected behaviour and all are fine.  One exception is send
+ * trailer fields.  You cannot send trailer fields after sending frame
+ * with END_STREAM set.  To avoid this problem, one can set
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_END_STREAM` along
+ * with :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_EOF` to signal the
+ * library not to set END_STREAM in DATA frame.  Then application can
+ * use `nghttp2_submit_trailer()` to send trailer fields.
  * `nghttp2_submit_trailer()` can be called inside this callback.
  *
  * If the application wants to postpone DATA frames (e.g.,
  * asynchronous I/O, or reading data blocks for long time), it is
- * achieved by returning :enum:`NGHTTP2_ERR_DEFERRED` without reading
- * any data in this invocation.  The library removes DATA frame from
- * the outgoing queue temporarily.  To move back deferred DATA frame
- * to outgoing queue, call `nghttp2_session_resume_data()`.
+ * achieved by returning :enum:`nghttp2_error.NGHTTP2_ERR_DEFERRED`
+ * without reading any data in this invocation.  The library removes
+ * DATA frame from the outgoing queue temporarily.  To move back
+ * deferred DATA frame to outgoing queue, call
+ * `nghttp2_session_resume_data()`.
  *
  * By default, |length| is limited to 16KiB at maximum.  If peer
  * allows larger frames, application can enlarge transmission buffer
@@ -900,16 +923,17 @@ typedef enum {
  *
  * If the application just wants to return from
  * `nghttp2_session_send()` or `nghttp2_session_mem_send()` without
- * sending anything, return :enum:`NGHTTP2_ERR_PAUSE`.
+ * sending anything, return :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE`.
  *
  * In case of error, there are 2 choices. Returning
- * :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will close the stream
- * by issuing RST_STREAM with :enum:`NGHTTP2_INTERNAL_ERROR`.  If a
- * different error code is desirable, use
- * `nghttp2_submit_rst_stream()` with a desired error code and then
- * return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  Returning
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` will signal the entire session
- * failure.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will
+ * close the stream by issuing RST_STREAM with
+ * :enum:`nghttp2_error_code.NGHTTP2_INTERNAL_ERROR`.  If a different
+ * error code is desirable, use `nghttp2_submit_rst_stream()` with a
+ * desired error code and then return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
+ * Returning :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` will
+ * signal the entire session failure.
  */
 typedef ssize_t (*nghttp2_data_source_read_callback)(
     nghttp2_session *session, int32_t stream_id, uint8_t *buf, size_t length,
@@ -1289,8 +1313,9 @@ typedef union {
  * |length| bytes of data stored in |data|.  The |flags| is currently
  * not used and always 0. It must return the number of bytes sent if
  * it succeeds.  If it cannot send any single byte without blocking,
- * it must return :enum:`NGHTTP2_ERR_WOULDBLOCK`.  For other errors,
- * it must return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  The
+ * it must return :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`.  For
+ * other errors, it must return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  The
  * |user_data| pointer is the third argument passed in to the call to
  * `nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
  *
@@ -1318,9 +1343,10 @@ typedef ssize_t (*nghttp2_send_callback)(nghttp2_session *session,
 /**
  * @functypedef
  *
- * Callback function invoked when :enum:`NGHTTP2_DATA_FLAG_NO_COPY` is
- * used in :type:`nghttp2_data_source_read_callback` to send complete
- * DATA frame.
+ * Callback function invoked when
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_COPY` is used in
+ * :type:`nghttp2_data_source_read_callback` to send complete DATA
+ * frame.
  *
  * The |frame| is a DATA frame to send.  The |framehd| is the
  * serialized frame header (9 bytes). The |length| is the length of
@@ -1338,21 +1364,22 @@ typedef ssize_t (*nghttp2_send_callback)(nghttp2_session *session,
  * If all data were written successfully, return 0.
  *
  * If it cannot send any data at all, just return
- * :enum:`NGHTTP2_ERR_WOULDBLOCK`; the library will call this callback
- * with the same parameters later (It is recommended to send complete
- * DATA frame at once in this function to deal with error; if partial
- * frame data has already sent, it is impossible to send another data
- * in that state, and all we can do is tear down connection).  When
- * data is fully processed, but application wants to make
- * `nghttp2_session_mem_send()` or `nghttp2_session_send()` return
- * immediately without processing next frames, return
- * :enum:`NGHTTP2_ERR_PAUSE`.  If application decided to reset this
- * stream, return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`, then
+ * :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`; the library will call
+ * this callback with the same parameters later (It is recommended to
+ * send complete DATA frame at once in this function to deal with
+ * error; if partial frame data has already sent, it is impossible to
+ * send another data in that state, and all we can do is tear down
+ * connection).  When data is fully processed, but application wants
+ * to make `nghttp2_session_mem_send()` or `nghttp2_session_send()`
+ * return immediately without processing next frames, return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE`.  If application decided to
+ * reset this stream, return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`, then
  * the library will send RST_STREAM with INTERNAL_ERROR as error code.
  * The application can also return
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`, which will result in
- * connection closure.  Returning any other value is treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`, which will
+ * result in connection closure.  Returning any other value is treated
+ * as :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` is returned.
  */
 typedef int (*nghttp2_send_data_callback)(nghttp2_session *session,
                                           nghttp2_frame *frame,
@@ -1369,11 +1396,13 @@ typedef int (*nghttp2_send_data_callback)(nghttp2_session *session,
  * currently not used and always 0.  It must return the number of
  * bytes written in |buf| if it succeeds.  If it cannot read any
  * single byte without blocking, it must return
- * :enum:`NGHTTP2_ERR_WOULDBLOCK`.  If it gets EOF before it reads any
- * single byte, it must return :enum:`NGHTTP2_ERR_EOF`.  For other
- * errors, it must return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
- * Returning 0 is treated as :enum:`NGHTTP2_ERR_WOULDBLOCK`.  The
- * |user_data| pointer is the third argument passed in to the call to
+ * :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`.  If it gets EOF
+ * before it reads any single byte, it must return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_EOF`.  For other errors, it must
+ * return :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * Returning 0 is treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`.  The |user_data|
+ * pointer is the third argument passed in to the call to
  * `nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
  *
  * This callback is required if the application uses
@@ -1417,7 +1446,8 @@ typedef ssize_t (*nghttp2_recv_callback)(nghttp2_session *session, uint8_t *buf,
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero value is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_frame_recv_callback()`.
@@ -1445,7 +1475,8 @@ typedef int (*nghttp2_on_frame_recv_callback)(nghttp2_session *session,
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_invalid_frame_recv_callback()`.
@@ -1468,9 +1499,9 @@ typedef int (*nghttp2_on_invalid_frame_recv_callback)(
  * `nghttp2_session_server_new()`.
  *
  * If the application uses `nghttp2_session_mem_recv()`, it can return
- * :enum:`NGHTTP2_ERR_PAUSE` to make `nghttp2_session_mem_recv()`
- * return without processing further input bytes.  The memory by
- * pointed by the |data| is retained until
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` to make
+ * `nghttp2_session_mem_recv()` return without processing further
+ * input bytes.  The memory by pointed by the |data| is retained until
  * `nghttp2_session_mem_recv()` or `nghttp2_session_recv()` is called.
  * The application must retain the input bytes which was used to
  * produce the |data| parameter, because it may refer to the memory
@@ -1479,7 +1510,8 @@ typedef int (*nghttp2_on_invalid_frame_recv_callback)(
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error, and
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_data_chunk_recv_callback()`.
@@ -1499,19 +1531,20 @@ typedef int (*nghttp2_on_data_chunk_recv_callback)(nghttp2_session *session,
  * `nghttp2_session_server_new()`.
  *
  * The implementation of this function must return 0 if it succeeds.
- * It can also return :enum:`NGHTTP2_ERR_CANCEL` to cancel the
- * transmission of the given frame.
+ * It can also return :enum:`nghttp2_error.NGHTTP2_ERR_CANCEL` to
+ * cancel the transmission of the given frame.
  *
  * If there is a fatal error while executing this callback, the
- * implementation should return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`,
- * which makes `nghttp2_session_send()` and
- * `nghttp2_session_mem_send()` functions immediately return
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * implementation should return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`, which makes
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * If the other value is returned, it is treated as if
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned.  But the
- * implementation should not rely on this since the library may define
- * new return value to extend its capability.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` is returned.
+ * But the implementation should not rely on this since the library
+ * may define new return value to extend its capability.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_before_frame_send_callback()`.
@@ -1530,7 +1563,8 @@ typedef int (*nghttp2_before_frame_send_callback)(nghttp2_session *session,
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_frame_send_callback()`.
@@ -1552,7 +1586,8 @@ typedef int (*nghttp2_on_frame_send_callback)(nghttp2_session *session,
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * `nghttp2_session_get_stream_user_data()` can be used to get
  * associated data.
@@ -1583,7 +1618,8 @@ typedef int (*nghttp2_on_frame_not_send_callback)(nghttp2_session *session,
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()`, `nghttp2_session_mem_recv()`,
  * `nghttp2_session_send()`, and `nghttp2_session_mem_send()`
- * functions immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * functions immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_stream_close_callback()`.
@@ -1601,10 +1637,11 @@ typedef int (*nghttp2_on_stream_close_callback)(nghttp2_session *session,
  * will be emitted by :type:`nghttp2_on_header_callback`.
  *
  * The ``frame->hd.flags`` may not have
- * :enum:`NGHTTP2_FLAG_END_HEADERS` flag set, which indicates that one
- * or more CONTINUATION frames are involved.  But the application does
- * not need to care about that because the header name/value pairs are
- * emitted transparently regardless of CONTINUATION frames.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_END_HEADERS` flag set, which
+ * indicates that one or more CONTINUATION frames are involved.  But
+ * the application does not need to care about that because the header
+ * name/value pairs are emitted transparently regardless of
+ * CONTINUATION frames.
  *
  * The server applications probably create an object to store
  * information about new stream if ``frame->hd.type ==
@@ -1627,26 +1664,31 @@ typedef int (*nghttp2_on_stream_close_callback)(nghttp2_session *session,
  * trailer fields also has ``frame->headers.cat ==
  * NGHTTP2_HCAT_HEADERS`` which does not contain any status code.
  *
- * Returning :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will close
- * the stream (promised stream if frame is PUSH_PROMISE) by issuing
- * RST_STREAM with :enum:`NGHTTP2_INTERNAL_ERROR`.  In this case,
+ * Returning
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will
+ * close the stream (promised stream if frame is PUSH_PROMISE) by
+ * issuing RST_STREAM with
+ * :enum:`nghttp2_error_code.NGHTTP2_INTERNAL_ERROR`.  In this case,
  * :type:`nghttp2_on_header_callback` and
  * :type:`nghttp2_on_frame_recv_callback` will not be invoked.  If a
  * different error code is desirable, use
  * `nghttp2_submit_rst_stream()` with a desired error code and then
- * return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  Again, use
- * ``frame->push_promise.promised_stream_id`` as stream_id parameter
- * in `nghttp2_submit_rst_stream()` if frame is PUSH_PROMISE.
+ * return :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
+ * Again, use ``frame->push_promise.promised_stream_id`` as stream_id
+ * parameter in `nghttp2_submit_rst_stream()` if frame is
+ * PUSH_PROMISE.
  *
  * The implementation of this function must return 0 if it succeeds.
- * It can return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` to
+ * It can return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` to
  * reset the stream (promised stream if frame is PUSH_PROMISE).  For
  * critical errors, it must return
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other value is
- * returned, it is treated as if :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`
- * is returned.  If :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other
+ * value is returned, it is treated as if
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` is returned.  If
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
  * `nghttp2_session_mem_recv()` function will immediately return
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_begin_headers_callback()`.
@@ -1663,16 +1705,17 @@ typedef int (*nghttp2_on_begin_headers_callback)(nghttp2_session *session,
  * The |value| of length |valuelen| is header value.  The |flags| is
  * bitwise OR of one or more of :type:`nghttp2_nv_flag`.
  *
- * If :enum:`NGHTTP2_NV_FLAG_NO_INDEX` is set in |flags|, the receiver
- * must not index this name/value pair when forwarding it to the next
- * hop.  More specifically, "Literal Header Field never Indexed"
- * representation must be used in HPACK encoding.
+ * If :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_INDEX` is set in
+ * |flags|, the receiver must not index this name/value pair when
+ * forwarding it to the next hop.  More specifically, "Literal Header
+ * Field never Indexed" representation must be used in HPACK encoding.
  *
  * When this callback is invoked, ``frame->hd.type`` is either
- * :enum:`NGHTTP2_HEADERS` or :enum:`NGHTTP2_PUSH_PROMISE`.  After all
- * header name/value pairs are processed with this callback, and no
- * error has been detected, :type:`nghttp2_on_frame_recv_callback`
- * will be invoked.  If there is an error in decompression,
+ * :enum:`nghttp2_frame_type.NGHTTP2_HEADERS` or
+ * :enum:`nghttp2_frame_type.NGHTTP2_PUSH_PROMISE`.  After all header
+ * name/value pairs are processed with this callback, and no error has
+ * been detected, :type:`nghttp2_on_frame_recv_callback` will be
+ * invoked.  If there is an error in decompression,
  * :type:`nghttp2_on_frame_recv_callback` for the |frame| will not be
  * invoked.
  *
@@ -1690,34 +1733,39 @@ typedef int (*nghttp2_on_begin_headers_callback)(nghttp2_session *session,
  * explained in :ref:`http-messaging` section.
  *
  * If the application uses `nghttp2_session_mem_recv()`, it can return
- * :enum:`NGHTTP2_ERR_PAUSE` to make `nghttp2_session_mem_recv()`
- * return without processing further input bytes.  The memory pointed
- * by |frame|, |name| and |value| parameters are retained until
- * `nghttp2_session_mem_recv()` or `nghttp2_session_recv()` is called.
- * The application must retain the input bytes which was used to
- * produce these parameters, because it may refer to the memory region
- * included in the input bytes.
- *
- * Returning :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will close
- * the stream (promised stream if frame is PUSH_PROMISE) by issuing
- * RST_STREAM with :enum:`NGHTTP2_INTERNAL_ERROR`.  In this case,
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` to make
+ * `nghttp2_session_mem_recv()` return without processing further
+ * input bytes.  The memory pointed by |frame|, |name| and |value|
+ * parameters are retained until `nghttp2_session_mem_recv()` or
+ * `nghttp2_session_recv()` is called.  The application must retain
+ * the input bytes which was used to produce these parameters, because
+ * it may refer to the memory region included in the input bytes.
+ *
+ * Returning
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will
+ * close the stream (promised stream if frame is PUSH_PROMISE) by
+ * issuing RST_STREAM with
+ * :enum:`nghttp2_error_code.NGHTTP2_INTERNAL_ERROR`.  In this case,
  * :type:`nghttp2_on_header_callback` and
  * :type:`nghttp2_on_frame_recv_callback` will not be invoked.  If a
  * different error code is desirable, use
  * `nghttp2_submit_rst_stream()` with a desired error code and then
- * return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  Again, use
- * ``frame->push_promise.promised_stream_id`` as stream_id parameter
- * in `nghttp2_submit_rst_stream()` if frame is PUSH_PROMISE.
+ * return :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
+ * Again, use ``frame->push_promise.promised_stream_id`` as stream_id
+ * parameter in `nghttp2_submit_rst_stream()` if frame is
+ * PUSH_PROMISE.
  *
  * The implementation of this function must return 0 if it succeeds.
- * It may return :enum:`NGHTTP2_ERR_PAUSE` or
- * :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  For other critical
- * failures, it must return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If
- * the other nonzero value is returned, it is treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
+ * It may return :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` or
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  For
+ * other critical failures, it must return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other
+ * nonzero value is returned, it is treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_header_callback()`.
@@ -1784,11 +1832,12 @@ typedef int (*nghttp2_on_header_callback2)(nghttp2_session *session,
  *
  * With this callback, application inspects the incoming invalid
  * field, and it also can reset stream from this callback by returning
- * :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  By default, the
- * error code is :enum:`NGHTTP2_PROTOCOL_ERROR`.  To change the error
- * code, call `nghttp2_submit_rst_stream()` with the error code of
- * choice in addition to returning
- * :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  By
+ * default, the error code is
+ * :enum:`nghttp2_error_code.NGHTTP2_PROTOCOL_ERROR`.  To change the
+ * error code, call `nghttp2_submit_rst_stream()` with the error code
+ * of choice in addition to returning
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
  *
  * If 0 is returned, the header field is ignored, and the stream is
  * not reset.
@@ -1819,11 +1868,12 @@ typedef int (*nghttp2_on_invalid_header_callback)(
  *
  * With this callback, application inspects the incoming invalid
  * field, and it also can reset stream from this callback by returning
- * :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  By default, the
- * error code is :enum:`NGHTTP2_INTERNAL_ERROR`.  To change the error
- * code, call `nghttp2_submit_rst_stream()` with the error code of
- * choice in addition to returning
- * :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  By
+ * default, the error code is
+ * :enum:`nghttp2_error_code.NGHTTP2_INTERNAL_ERROR`.  To change the
+ * error code, call `nghttp2_submit_rst_stream()` with the error code
+ * of choice in addition to returning
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
  */
 typedef int (*nghttp2_on_invalid_header_callback2)(
     nghttp2_session *session, const nghttp2_frame *frame, nghttp2_rcbuf *name,
@@ -1837,11 +1887,12 @@ typedef int (*nghttp2_on_invalid_header_callback2)(
  * |frame|.  The application must choose the total length of payload
  * including padded bytes in range [frame->hd.length, max_payloadlen],
  * inclusive.  Choosing number not in this range will be treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  Returning
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  Returning
  * ``frame->hd.length`` means no padding is added.  Returning
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` will make
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` will make
  * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_select_padding_callback()`.
@@ -1861,16 +1912,17 @@ typedef ssize_t (*nghttp2_select_padding_callback)(nghttp2_session *session,
  * |remote_max_frame_size|)].  If a value greater than this range is
  * returned than the max allow value will be used.  Returning a value
  * smaller than this range is treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  The |frame_type| is provided
- * for future extensibility and identifies the type of frame (see
- * :type:`nghttp2_frame_type`) for which to get the length for.
- * Currently supported frame types are: :enum:`NGHTTP2_DATA`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  The
+ * |frame_type| is provided for future extensibility and identifies
+ * the type of frame (see :type:`nghttp2_frame_type`) for which to get
+ * the length for.  Currently supported frame types are:
+ * :enum:`nghttp2_frame_type.NGHTTP2_DATA`.
  *
  * This callback can be used to control the length in bytes for which
  * :type:`nghttp2_data_source_read_callback` is allowed to send to the
  * remote endpoint.  This callback is optional.  Returning
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` will signal the entire session
- * failure.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` will signal the
+ * entire session failure.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_data_source_read_length_callback()`.
@@ -1897,7 +1949,8 @@ typedef ssize_t (*nghttp2_data_source_read_length_callback)(
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero value is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_begin_frame_callback()`.
@@ -1916,14 +1969,15 @@ typedef int (*nghttp2_on_begin_frame_callback)(nghttp2_session *session,
  * The implementation of this function must return 0 if it succeeds.
  *
  * To abort processing this extension frame, return
- * :enum:`NGHTTP2_ERR_CANCEL`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CANCEL`.
  *
  * If fatal error occurred, application should return
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the
- * other values are returned, currently they are treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other
+ * values are returned, currently they are treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  */
 typedef int (*nghttp2_on_extension_chunk_recv_callback)(
     nghttp2_session *session, const nghttp2_frame_hd *hd, const uint8_t *data,
@@ -1953,14 +2007,15 @@ typedef int (*nghttp2_on_extension_chunk_recv_callback)(
  * |*payload|, and do its own mechanism to process extension frames.
  *
  * To abort processing this extension frame, return
- * :enum:`NGHTTP2_ERR_CANCEL`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CANCEL`.
  *
  * If fatal error occurred, application should return
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the
- * other values are returned, currently they are treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other
+ * values are returned, currently they are treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  */
 typedef int (*nghttp2_unpack_extension_callback)(nghttp2_session *session,
                                                  void **payload,
@@ -1982,17 +2037,18 @@ typedef int (*nghttp2_unpack_extension_callback)(nghttp2_session *session,
  * bytes written into |buf| when it succeeds.
  *
  * To abort processing this extension frame, return
- * :enum:`NGHTTP2_ERR_CANCEL`, and
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CANCEL`, and
  * :type:`nghttp2_on_frame_not_send_callback` will be invoked.
  *
  * If fatal error occurred, application should return
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
  * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the
- * other values are returned, currently they are treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the return value is
- * strictly larger than |len|, it is treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other
+ * values are returned, currently they are treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the return
+ * value is strictly larger than |len|, it is treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  */
 typedef ssize_t (*nghttp2_pack_extension_callback)(nghttp2_session *session,
                                                    uint8_t *buf, size_t len,
@@ -2017,12 +2073,12 @@ typedef ssize_t (*nghttp2_pack_extension_callback)(nghttp2_session *session,
  *
  * Normally, application should return 0 from this callback.  If fatal
  * error occurred while doing something in this callback, application
- * should return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
- * library will return immediately with return value
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  Currently, if nonzero value
- * is returned from this callback, they are treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`, but application should not
- * rely on this details.
+ * should return :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * In this case, library will return immediately with return value
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  Currently, if
+ * nonzero value is returned from this callback, they are treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`, but application
+ * should not rely on this details.
  */
 typedef int (*nghttp2_error_callback)(nghttp2_session *session, const char *msg,
                                       size_t len, void *user_data);
@@ -2043,12 +2099,12 @@ typedef int (*nghttp2_error_callback)(nghttp2_session *session, const char *msg,
  *
  * Normally, application should return 0 from this callback.  If fatal
  * error occurred while doing something in this callback, application
- * should return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
- * library will return immediately with return value
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  Currently, if nonzero value
- * is returned from this callback, they are treated as
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`, but application should not
- * rely on this details.
+ * should return :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * In this case, library will return immediately with return value
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  Currently, if
+ * nonzero value is returned from this callback, they are treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`, but application
+ * should not rely on this details.
  */
 typedef int (*nghttp2_error_callback2)(nghttp2_session *session,
                                        int lib_error_code, const char *msg,
@@ -2078,7 +2134,7 @@ typedef struct nghttp2_session_callbacks nghttp2_session_callbacks;
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int
@@ -2275,7 +2331,7 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_on_begin_frame_callback(
  * @function
  *
  * Sets callback function invoked when
- * :enum:`NGHTTP2_DATA_FLAG_NO_COPY` is used in
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_COPY` is used in
  * :type:`nghttp2_data_source_read_callback` to avoid data copy.
  */
 NGHTTP2_EXTERN void nghttp2_session_callbacks_set_send_data_callback(
@@ -2458,7 +2514,7 @@ typedef struct nghttp2_option nghttp2_option;
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_option_new(nghttp2_option **option_ptr);
@@ -2519,7 +2575,8 @@ nghttp2_option_set_peer_max_concurrent_streams(nghttp2_option *option,
  * If this option is not used or used with zero value, if MAGIC does
  * not match :macro:`NGHTTP2_CLIENT_MAGIC`, `nghttp2_session_recv()`
  * and `nghttp2_session_mem_recv()` will return error
- * :enum:`NGHTTP2_ERR_BAD_CLIENT_MAGIC`, which is fatal error.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_BAD_CLIENT_MAGIC`, which is fatal
+ * error.
  */
 NGHTTP2_EXTERN void
 nghttp2_option_set_no_recv_client_magic(nghttp2_option *option, int val);
@@ -2604,8 +2661,8 @@ nghttp2_option_set_builtin_recv_extension_type(nghttp2_option *option,
  * received.  If this option is set to nonzero, the library won't send
  * PING frame with ACK flag set in the response for incoming PING
  * frame.  The application can send PING frame with ACK flag set using
- * `nghttp2_submit_ping()` with :enum:`NGHTTP2_FLAG_ACK` as flags
- * parameter.
+ * `nghttp2_submit_ping()` with :enum:`nghttp2_flag.NGHTTP2_FLAG_ACK`
+ * as flags parameter.
  */
 NGHTTP2_EXTERN void nghttp2_option_set_no_auto_ping_ack(nghttp2_option *option,
                                                         int val);
@@ -2619,7 +2676,7 @@ NGHTTP2_EXTERN void nghttp2_option_set_no_auto_ping_ack(nghttp2_option *option,
  * `nghttp2_hd_deflate_bound()`.  The default value is 64KiB.  If
  * application attempts to send header fields larger than this limit,
  * the transmission of the frame fails with error code
- * :enum:`NGHTTP2_ERR_FRAME_SIZE_ERROR`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_FRAME_SIZE_ERROR`.
  */
 NGHTTP2_EXTERN void
 nghttp2_option_set_max_send_header_block_length(nghttp2_option *option,
@@ -2644,6 +2701,11 @@ nghttp2_option_set_max_deflate_dynamic_table_size(nghttp2_option *option,
  * This option prevents the library from retaining closed streams to
  * maintain the priority tree.  If this option is set to nonzero,
  * applications can discard closed stream completely to save memory.
+ *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 1 is submitted via `nghttp2_submit_settings()`, any
+ * closed streams are not retained regardless of this option.
  */
 NGHTTP2_EXTERN void nghttp2_option_set_no_closed_streams(nghttp2_option *option,
                                                          int val);
@@ -2662,6 +2724,47 @@ NGHTTP2_EXTERN void nghttp2_option_set_max_outbound_ack(nghttp2_option *option,
 /**
  * @function
  *
+ * This function sets the maximum number of SETTINGS entries per
+ * SETTINGS frame that will be accepted. If more than those entries
+ * are received, the peer is considered to be misbehaving and session
+ * will be closed. The default value is 32.
+ */
+NGHTTP2_EXTERN void nghttp2_option_set_max_settings(nghttp2_option *option,
+                                                    size_t val);
+
+/**
+ * @function
+ *
+ * This option, if set to nonzero, allows server to fallback to
+ * :rfc:`7540` priorities if SETTINGS_NO_RFC7540_PRIORITIES was not
+ * received from client, and server submitted
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * = 1 via `nghttp2_submit_settings()`.  Most of the advanced
+ * functionality for RFC 7540 priorities are still disabled.  This
+ * fallback only enables the minimal feature set of RFC 7540
+ * priorities to deal with priority signaling from client.
+ *
+ * Client session ignores this option.
+ */
+NGHTTP2_EXTERN void
+nghttp2_option_set_server_fallback_rfc7540_priorities(nghttp2_option *option,
+                                                      int val);
+
+/**
+ * @function
+ *
+ * This option, if set to nonzero, turns off RFC 9113 leading and
+ * trailing white spaces validation against HTTP field value.  Some
+ * important fields, such as HTTP/2 pseudo header fields, are
+ * validated more strictly and this option does not apply to them.
+ */
+NGHTTP2_EXTERN void
+nghttp2_option_set_no_rfc9113_leading_and_trailing_ws_validation(
+    nghttp2_option *option, int val);
+
+/**
+ * @function
+ *
  * Initializes |*session_ptr| for client use.  The all members of
  * |callbacks| are copied to |*session_ptr|.  Therefore |*session_ptr|
  * does not store |callbacks|.  The |user_data| is an arbitrary user
@@ -2677,7 +2780,7 @@ NGHTTP2_EXTERN void nghttp2_option_set_max_outbound_ack(nghttp2_option *option,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int
@@ -2703,7 +2806,7 @@ nghttp2_session_client_new(nghttp2_session **session_ptr,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int
@@ -2729,7 +2832,7 @@ nghttp2_session_server_new(nghttp2_session **session_ptr,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int
@@ -2755,7 +2858,7 @@ nghttp2_session_client_new2(nghttp2_session **session_ptr,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int
@@ -2781,7 +2884,7 @@ nghttp2_session_server_new2(nghttp2_session **session_ptr,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_session_client_new3(
@@ -2806,7 +2909,7 @@ NGHTTP2_EXTERN int nghttp2_session_client_new3(
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_session_server_new3(
@@ -2828,12 +2931,14 @@ NGHTTP2_EXTERN void nghttp2_session_del(nghttp2_session *session);
  *
  * This function retrieves the highest prioritized frame from the
  * outbound queue and sends it to the remote peer.  It does this as
- * many as possible until the user callback
+ * many times as possible until the user callback
  * :type:`nghttp2_send_callback` returns
- * :enum:`NGHTTP2_ERR_WOULDBLOCK` or the outbound queue becomes empty.
- * This function calls several callback functions which are passed
- * when initializing the |session|.  Here is the simple time chart
- * which tells when each callback is invoked:
+ * :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`, the outbound queue
+ * becomes empty or flow control is triggered (remote window size
+ * becomes depleted or maximum number of concurrent streams is
+ * reached).  This function calls several callback functions which are
+ * passed when initializing the |session|.  Here is the simple time
+ * chart which tells when each callback is invoked:
  *
  * 1. Get the next frame to send from outbound queue.
  *
@@ -2851,7 +2956,7 @@ NGHTTP2_EXTERN void nghttp2_session_del(nghttp2_session *session);
  *
  * 6. :type:`nghttp2_before_frame_send_callback` is invoked.
  *
- * 7. If :enum:`NGHTTP2_ERR_CANCEL` is returned from
+ * 7. If :enum:`nghttp2_error.NGHTTP2_ERR_CANCEL` is returned from
  *    :type:`nghttp2_before_frame_send_callback`, the current frame
  *    transmission is canceled, and
  *    :type:`nghttp2_on_frame_not_send_callback` is invoked.  Abort
@@ -2869,9 +2974,9 @@ NGHTTP2_EXTERN void nghttp2_session_del(nghttp2_session *session);
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`
  *     The callback function failed.
  */
 NGHTTP2_EXTERN int nghttp2_session_send(nghttp2_session *session);
@@ -2903,7 +3008,7 @@ NGHTTP2_EXTERN int nghttp2_session_send(nghttp2_session *session);
  * |*data_ptr| if it succeeds, or one of the following negative error
  * codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  *
  * .. note::
@@ -2925,8 +3030,8 @@ NGHTTP2_EXTERN ssize_t nghttp2_session_mem_send(nghttp2_session *session,
  *
  * This function receives as many frames as possible until the user
  * callback :type:`nghttp2_recv_callback` returns
- * :enum:`NGHTTP2_ERR_WOULDBLOCK`.  This function calls several
- * callback functions which are passed when initializing the
+ * :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`.  This function calls
+ * several callback functions which are passed when initializing the
  * |session|.  Here is the simple time chart which tells when each
  * callback is invoked:
  *
@@ -2971,18 +3076,18 @@ NGHTTP2_EXTERN ssize_t nghttp2_session_mem_send(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_EOF`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_EOF`
  *     The remote peer did shutdown on the connection.
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`
  *     The callback function failed.
- * :enum:`NGHTTP2_ERR_BAD_CLIENT_MAGIC`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_BAD_CLIENT_MAGIC`
  *     Invalid client magic was detected.  This error only returns
  *     when |session| was configured as server and
  *     `nghttp2_option_set_no_recv_client_magic()` is not used with
  *     nonzero value.
- * :enum:`NGHTTP2_ERR_FLOODED`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_FLOODED`
  *     Flooding was detected in this HTTP/2 session, and it must be
  *     closed.  This is most likely caused by misbehaviour of peer.
  */
@@ -2992,7 +3097,7 @@ NGHTTP2_EXTERN int nghttp2_session_recv(nghttp2_session *session);
  * @function
  *
  * Processes data |in| as an input from the remote endpoint.  The
- * |inlen| indicates the number of bytes in the |in|.
+ * |inlen| indicates the number of bytes to receive in the |in|.
  *
  * This function behaves like `nghttp2_session_recv()` except that it
  * does not use :type:`nghttp2_recv_callback` to receive data; the
@@ -3001,27 +3106,27 @@ NGHTTP2_EXTERN int nghttp2_session_recv(nghttp2_session *session);
  * are called in the same way as they are in `nghttp2_session_recv()`.
  *
  * In the current implementation, this function always tries to
- * processes all input data unless either an error occurs or
- * :enum:`NGHTTP2_ERR_PAUSE` is returned from
+ * processes |inlen| bytes of input data unless either an error occurs or
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` is returned from
  * :type:`nghttp2_on_header_callback` or
  * :type:`nghttp2_on_data_chunk_recv_callback`.  If
- * :enum:`NGHTTP2_ERR_PAUSE` is used, the return value includes the
- * number of bytes which was used to produce the data or frame for the
- * callback.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` is used, the return value
+ * includes the number of bytes which was used to produce the data or
+ * frame for the callback.
  *
  * This function returns the number of processed bytes, or one of the
  * following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`
  *     The callback function failed.
- * :enum:`NGHTTP2_ERR_BAD_CLIENT_MAGIC`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_BAD_CLIENT_MAGIC`
  *     Invalid client magic was detected.  This error only returns
  *     when |session| was configured as server and
  *     `nghttp2_option_set_no_recv_client_magic()` is not used with
  *     nonzero value.
- * :enum:`NGHTTP2_ERR_FLOODED`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_FLOODED`
  *     Flooding was detected in this HTTP/2 session, and it must be
  *     closed.  This is most likely caused by misbehaviour of peer.
  */
@@ -3038,9 +3143,9 @@ NGHTTP2_EXTERN ssize_t nghttp2_session_mem_recv(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The stream does not exist; or no deferred data exist.
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_session_resume_data(nghttp2_session *session,
@@ -3101,7 +3206,7 @@ nghttp2_session_get_stream_user_data(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The stream does not exist
  */
 NGHTTP2_EXTERN int
@@ -3318,7 +3423,7 @@ nghttp2_session_get_hd_deflate_dynamic_table_size(nghttp2_session *session);
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_session_terminate_session(nghttp2_session *session,
@@ -3345,9 +3450,9 @@ NGHTTP2_EXTERN int nghttp2_session_terminate_session(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |last_stream_id| is invalid.
  */
 NGHTTP2_EXTERN int nghttp2_session_terminate_session2(nghttp2_session *session,
@@ -3362,7 +3467,7 @@ NGHTTP2_EXTERN int nghttp2_session_terminate_session2(nghttp2_session *session,
  *
  * This function is only usable for server.  If this function is
  * called with client side session, this function returns
- * :enum:`NGHTTP2_ERR_INVALID_STATE`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`.
  *
  * To gracefully shutdown HTTP/2 session, server should call this
  * function to send GOAWAY with last_stream_id (1u << 31) - 1.  And
@@ -3384,9 +3489,9 @@ NGHTTP2_EXTERN int nghttp2_session_terminate_session2(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
  *     The |session| is initialized as client.
  */
 NGHTTP2_EXTERN int nghttp2_submit_shutdown_notice(nghttp2_session *session);
@@ -3421,7 +3526,7 @@ NGHTTP2_EXTERN uint32_t nghttp2_session_get_local_settings(
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |next_stream_id| is strictly less than the value
  *     `nghttp2_session_get_next_stream_id()` returns; or
  *     |next_stream_id| is invalid (e.g., even integer for client, or
@@ -3456,11 +3561,11 @@ nghttp2_session_get_next_stream_id(nghttp2_session *session);
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0.
- * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
  *     Automatic WINDOW_UPDATE is not disabled.
  */
 NGHTTP2_EXTERN int nghttp2_session_consume(nghttp2_session *session,
@@ -3477,9 +3582,9 @@ NGHTTP2_EXTERN int nghttp2_session_consume(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
  *     Automatic WINDOW_UPDATE is not disabled.
  */
 NGHTTP2_EXTERN int nghttp2_session_consume_connection(nghttp2_session *session,
@@ -3496,11 +3601,11 @@ NGHTTP2_EXTERN int nghttp2_session_consume_connection(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0.
- * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
  *     Automatic WINDOW_UPDATE is not disabled.
  */
 NGHTTP2_EXTERN int nghttp2_session_consume_stream(nghttp2_session *session,
@@ -3527,12 +3632,17 @@ NGHTTP2_EXTERN int nghttp2_session_consume_stream(nghttp2_session *session,
  * found, we use default priority instead of given |pri_spec|.  That
  * is make stream depend on root stream with weight 16.
  *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 1 is submitted via `nghttp2_submit_settings()`, this
+ * function does nothing and returns 0.
+ *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     Attempted to depend on itself; or no stream exist for the given
  *     |stream_id|; or |stream_id| is 0
  */
@@ -3570,12 +3680,17 @@ nghttp2_session_change_stream_priority(nghttp2_session *session,
  * found, we use default priority instead of given |pri_spec|.  That
  * is make stream depend on root stream with weight 16.
  *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 1 is submitted via `nghttp2_submit_settings()`, this
+ * function does nothing and returns 0.
+ *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     Attempted to depend on itself; or stream denoted by |stream_id|
  *     already exists; or |stream_id| cannot be used to create idle
  *     stream (in other words, local endpoint has already opened
@@ -3626,11 +3741,11 @@ nghttp2_session_create_idle_stream(nghttp2_session *session, int32_t stream_id,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |settings_payload| is badly formed.
- * :enum:`NGHTTP2_ERR_PROTO`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
  *     The stream ID 1 is already used or closed; or is not available.
  */
 NGHTTP2_EXTERN int nghttp2_session_upgrade(nghttp2_session *session,
@@ -3670,11 +3785,11 @@ NGHTTP2_EXTERN int nghttp2_session_upgrade(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |settings_payload| is badly formed.
- * :enum:`NGHTTP2_ERR_PROTO`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
  *     The stream ID 1 is already used or closed; or is not available.
  */
 NGHTTP2_EXTERN int nghttp2_session_upgrade2(nghttp2_session *session,
@@ -3698,10 +3813,10 @@ NGHTTP2_EXTERN int nghttp2_session_upgrade2(nghttp2_session *session,
  * This function returns the number of bytes written in |buf|, or one
  * of the following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |iv| contains duplicate settings ID or invalid value.
  *
- * :enum:`NGHTTP2_ERR_INSUFF_BUFSIZE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`
  *     The provided |buflen| size is too small to hold the output.
  */
 NGHTTP2_EXTERN ssize_t nghttp2_pack_settings_payload(
@@ -3732,8 +3847,8 @@ NGHTTP2_EXTERN const char *nghttp2_http2_strerror(uint32_t error_code);
  * on with |weight| and its exclusive flag.  If |exclusive| is
  * nonzero, exclusive flag is set.
  *
- * The |weight| must be in [:enum:`NGHTTP2_MIN_WEIGHT`,
- * :enum:`NGHTTP2_MAX_WEIGHT`], inclusive.
+ * The |weight| must be in [:macro:`NGHTTP2_MIN_WEIGHT`,
+ * :macro:`NGHTTP2_MAX_WEIGHT`], inclusive.
  */
 NGHTTP2_EXTERN void nghttp2_priority_spec_init(nghttp2_priority_spec *pri_spec,
                                                int32_t stream_id,
@@ -3768,11 +3883,17 @@ nghttp2_priority_spec_check_default(const nghttp2_priority_spec *pri_spec);
  * use `nghttp2_priority_spec_init()`.  If |pri_spec| is not ``NULL``,
  * this function will copy its data members.
  *
- * The ``pri_spec->weight`` must be in [:enum:`NGHTTP2_MIN_WEIGHT`,
- * :enum:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight`` is
- * strictly less than :enum:`NGHTTP2_MIN_WEIGHT`, it becomes
- * :enum:`NGHTTP2_MIN_WEIGHT`.  If it is strictly greater than
- * :enum:`NGHTTP2_MAX_WEIGHT`, it becomes :enum:`NGHTTP2_MAX_WEIGHT`.
+ * The ``pri_spec->weight`` must be in [:macro:`NGHTTP2_MIN_WEIGHT`,
+ * :macro:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight``
+ * is strictly less than :macro:`NGHTTP2_MIN_WEIGHT`, it becomes
+ * :macro:`NGHTTP2_MIN_WEIGHT`.  If it is strictly greater than
+ * :macro:`NGHTTP2_MAX_WEIGHT`, it becomes
+ * :macro:`NGHTTP2_MAX_WEIGHT`.
+ *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 1 is received by a remote endpoint, |pri_spec| is
+ * ignored, and treated as if ``NULL`` is specified.
  *
  * The |nva| is an array of name/value pair :type:`nghttp2_nv` with
  * |nvlen| elements.  The application is responsible to include
@@ -3783,12 +3904,12 @@ nghttp2_priority_spec_check_default(const nghttp2_priority_spec *pri_spec);
  * This function creates copies of all name/value pairs in |nva|.  It
  * also lower-cases all names in |nva|.  The order of elements in
  * |nva| is preserved.  For header fields with
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME` and
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set, header field name
- * and value are not copied respectively.  With
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME`, application is responsible to
- * pass header field name in lowercase.  The application should
- * maintain the references to them until
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME` and
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set,
+ * header field name and value are not copied respectively.  With
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`, application
+ * is responsible to pass header field name in lowercase.  The
+ * application should maintain the references to them until
  * :type:`nghttp2_on_frame_send_callback` or
  * :type:`nghttp2_on_frame_not_send_callback` is called.
  *
@@ -3810,15 +3931,15 @@ nghttp2_priority_spec_check_default(const nghttp2_priority_spec *pri_spec);
  * This function returns assigned stream ID if it succeeds, or one of
  * the following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE`
  *     No stream ID is available because maximum stream ID was
  *     reached.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     Trying to depend on itself (new stream ID equals
  *     ``pri_spec->stream_id``).
- * :enum:`NGHTTP2_ERR_PROTO`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
  *     The |session| is server session.
  *
  * .. warning::
@@ -3853,12 +3974,12 @@ NGHTTP2_EXTERN int32_t nghttp2_submit_request(
  * This function creates copies of all name/value pairs in |nva|.  It
  * also lower-cases all names in |nva|.  The order of elements in
  * |nva| is preserved.  For header fields with
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME` and
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set, header field name
- * and value are not copied respectively.  With
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME`, application is responsible to
- * pass header field name in lowercase.  The application should
- * maintain the references to them until
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME` and
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set,
+ * header field name and value are not copied respectively.  With
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`, application
+ * is responsible to pass header field name in lowercase.  The
+ * application should maintain the references to them until
  * :type:`nghttp2_on_frame_send_callback` or
  * :type:`nghttp2_on_frame_not_send_callback` is called.
  *
@@ -3884,16 +4005,16 @@ NGHTTP2_EXTERN int32_t nghttp2_submit_request(
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0.
- * :enum:`NGHTTP2_ERR_DATA_EXIST`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_DATA_EXIST`
  *     DATA or HEADERS has been already submitted and not fully
  *     processed yet.  Normally, this does not happen, but when
  *     application wrongly calls `nghttp2_submit_response()` twice,
  *     this may happen.
- * :enum:`NGHTTP2_ERR_PROTO`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
  *     The |session| is client session.
  *
  * .. warning::
@@ -3919,12 +4040,12 @@ nghttp2_submit_response(nghttp2_session *session, int32_t stream_id,
  * This function creates copies of all name/value pairs in |nva|.  It
  * also lower-cases all names in |nva|.  The order of elements in
  * |nva| is preserved.  For header fields with
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME` and
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set, header field name
- * and value are not copied respectively.  With
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME`, application is responsible to
- * pass header field name in lowercase.  The application should
- * maintain the references to them until
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME` and
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set,
+ * header field name and value are not copied respectively.  With
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`, application
+ * is responsible to pass header field name in lowercase.  The
+ * application should maintain the references to them until
  * :type:`nghttp2_on_frame_send_callback` or
  * :type:`nghttp2_on_frame_not_send_callback` is called.
  *
@@ -3936,16 +4057,16 @@ nghttp2_submit_response(nghttp2_session *session, int32_t stream_id,
  * |nva| will be sent as response headers, which will result in error.
  *
  * This function has the same effect with `nghttp2_submit_headers()`,
- * with flags = :enum:`NGHTTP2_FLAG_END_STREAM` and both pri_spec and
- * stream_user_data to NULL.
+ * with flags = :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM` and both
+ * pri_spec and stream_user_data to NULL.
  *
  * To submit trailer fields after `nghttp2_submit_response()` is
  * called, the application has to specify
  * :type:`nghttp2_data_provider` to `nghttp2_submit_response()`.
  * Inside of :type:`nghttp2_data_source_read_callback`, when setting
- * :enum:`NGHTTP2_DATA_FLAG_EOF`, also set
- * :enum:`NGHTTP2_DATA_FLAG_NO_END_STREAM`.  After that, the
- * application can send trailer fields using
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_EOF`, also set
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_END_STREAM`.  After
+ * that, the application can send trailer fields using
  * `nghttp2_submit_trailer()`.  `nghttp2_submit_trailer()` can be used
  * inside :type:`nghttp2_data_source_read_callback`.
  *
@@ -3953,9 +4074,9 @@ nghttp2_submit_response(nghttp2_session *session, int32_t stream_id,
  * Otherwise, this function returns 0 if it succeeds, or one of the
  * following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0.
  */
 NGHTTP2_EXTERN int nghttp2_submit_trailer(nghttp2_session *session,
@@ -3968,10 +4089,10 @@ NGHTTP2_EXTERN int nghttp2_submit_trailer(nghttp2_session *session,
  * Submits HEADERS frame. The |flags| is bitwise OR of the
  * following values:
  *
- * * :enum:`NGHTTP2_FLAG_END_STREAM`
+ * * :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM`
  *
- * If |flags| includes :enum:`NGHTTP2_FLAG_END_STREAM`, this frame has
- * END_STREAM flag set.
+ * If |flags| includes :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM`,
+ * this frame has END_STREAM flag set.
  *
  * The library handles the CONTINUATION frame internally and it
  * correctly sets END_HEADERS to the last sequence of the PUSH_PROMISE
@@ -3988,11 +4109,16 @@ NGHTTP2_EXTERN int nghttp2_submit_trailer(nghttp2_session *session,
  * use `nghttp2_priority_spec_init()`.  If |pri_spec| is not ``NULL``,
  * this function will copy its data members.
  *
- * The ``pri_spec->weight`` must be in [:enum:`NGHTTP2_MIN_WEIGHT`,
- * :enum:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight`` is
- * strictly less than :enum:`NGHTTP2_MIN_WEIGHT`, it becomes
- * :enum:`NGHTTP2_MIN_WEIGHT`.  If it is strictly greater than
- * :enum:`NGHTTP2_MAX_WEIGHT`, it becomes :enum:`NGHTTP2_MAX_WEIGHT`.
+ * The ``pri_spec->weight`` must be in [:macro:`NGHTTP2_MIN_WEIGHT`,
+ * :macro:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight``
+ * is strictly less than :macro:`NGHTTP2_MIN_WEIGHT`, it becomes
+ * :macro:`NGHTTP2_MIN_WEIGHT`.  If it is strictly greater than
+ * :macro:`NGHTTP2_MAX_WEIGHT`, it becomes :macro:`NGHTTP2_MAX_WEIGHT`.
+ *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 1 is received by a remote endpoint, |pri_spec| is
+ * ignored, and treated as if ``NULL`` is specified.
  *
  * The |nva| is an array of name/value pair :type:`nghttp2_nv` with
  * |nvlen| elements.  The application is responsible to include
@@ -4003,12 +4129,12 @@ NGHTTP2_EXTERN int nghttp2_submit_trailer(nghttp2_session *session,
  * This function creates copies of all name/value pairs in |nva|.  It
  * also lower-cases all names in |nva|.  The order of elements in
  * |nva| is preserved.  For header fields with
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME` and
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set, header field name
- * and value are not copied respectively.  With
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME`, application is responsible to
- * pass header field name in lowercase.  The application should
- * maintain the references to them until
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME` and
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set,
+ * header field name and value are not copied respectively.  With
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`, application
+ * is responsible to pass header field name in lowercase.  The
+ * application should maintain the references to them until
  * :type:`nghttp2_on_frame_send_callback` or
  * :type:`nghttp2_on_frame_not_send_callback` is called.
  *
@@ -4026,19 +4152,19 @@ NGHTTP2_EXTERN int nghttp2_submit_trailer(nghttp2_session *session,
  * |stream_id| is -1.  Otherwise, this function returns 0 if it
  * succeeds, or one of the following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE`
  *     No stream ID is available because maximum stream ID was
  *     reached.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0; or trying to depend on itself (stream ID
  *     equals ``pri_spec->stream_id``).
- * :enum:`NGHTTP2_ERR_DATA_EXIST`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_DATA_EXIST`
  *     DATA or HEADERS has been already submitted and not fully
  *     processed yet.  This happens if stream denoted by |stream_id|
  *     is in reserved state.
- * :enum:`NGHTTP2_ERR_PROTO`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
  *     The |stream_id| is -1, and |session| is server session.
  *
  * .. warning::
@@ -4060,8 +4186,8 @@ NGHTTP2_EXTERN int32_t nghttp2_submit_headers(
  *
  * Submits one or more DATA frames to the stream |stream_id|.  The
  * data to be sent are provided by |data_prd|.  If |flags| contains
- * :enum:`NGHTTP2_FLAG_END_STREAM`, the last DATA frame has END_STREAM
- * flag set.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM`, the last DATA frame
+ * has END_STREAM flag set.
  *
  * This function does not take ownership of the |data_prd|.  The
  * function copies the members of the |data_prd|.
@@ -4069,27 +4195,28 @@ NGHTTP2_EXTERN int32_t nghttp2_submit_headers(
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_DATA_EXIST`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_DATA_EXIST`
  *     DATA or HEADERS has been already submitted and not fully
  *     processed yet.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0.
- * :enum:`NGHTTP2_ERR_STREAM_CLOSED`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_STREAM_CLOSED`
  *     The stream was already closed; or the |stream_id| is invalid.
  *
  * .. note::
  *
  *   Currently, only one DATA or HEADERS is allowed for a stream at a
  *   time.  Submitting these frames more than once before first DATA
- *   or HEADERS is finished results in :enum:`NGHTTP2_ERR_DATA_EXIST`
- *   error code.  The earliest callback which tells that previous
- *   frame is done is :type:`nghttp2_on_frame_send_callback`.  In side
- *   that callback, new data can be submitted using
- *   `nghttp2_submit_data()`.  Of course, all data except for last one
- *   must not have :enum:`NGHTTP2_FLAG_END_STREAM` flag set in
- *   |flags|.  This sounds a bit complicated, and we recommend to use
+ *   or HEADERS is finished results in
+ *   :enum:`nghttp2_error.NGHTTP2_ERR_DATA_EXIST` error code.  The
+ *   earliest callback which tells that previous frame is done is
+ *   :type:`nghttp2_on_frame_send_callback`.  In side that callback,
+ *   new data can be submitted using `nghttp2_submit_data()`.  Of
+ *   course, all data except for last one must not have
+ *   :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM` flag set in |flags|.
+ *   This sounds a bit complicated, and we recommend to use
  *   `nghttp2_submit_request()` and `nghttp2_submit_response()` to
  *   avoid this cascading issue.  The experience shows that for HTTP
  *   use, these two functions are enough to implement both client and
@@ -4106,25 +4233,31 @@ NGHTTP2_EXTERN int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
  * to the priority specification |pri_spec|.
  *
  * The |flags| is currently ignored and should be
- * :enum:`NGHTTP2_FLAG_NONE`.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * The |pri_spec| is priority specification of this request.  ``NULL``
  * is not allowed for this function. To specify the priority, use
  * `nghttp2_priority_spec_init()`.  This function will copy its data
  * members.
  *
- * The ``pri_spec->weight`` must be in [:enum:`NGHTTP2_MIN_WEIGHT`,
- * :enum:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight`` is
- * strictly less than :enum:`NGHTTP2_MIN_WEIGHT`, it becomes
- * :enum:`NGHTTP2_MIN_WEIGHT`.  If it is strictly greater than
- * :enum:`NGHTTP2_MAX_WEIGHT`, it becomes :enum:`NGHTTP2_MAX_WEIGHT`.
+ * The ``pri_spec->weight`` must be in [:macro:`NGHTTP2_MIN_WEIGHT`,
+ * :macro:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight``
+ * is strictly less than :macro:`NGHTTP2_MIN_WEIGHT`, it becomes
+ * :macro:`NGHTTP2_MIN_WEIGHT`.  If it is strictly greater than
+ * :macro:`NGHTTP2_MAX_WEIGHT`, it becomes
+ * :macro:`NGHTTP2_MAX_WEIGHT`.
+ *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 1 is received by a remote endpoint, this function does
+ * nothing and returns 0.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0; or the |pri_spec| is NULL; or trying to
  *     depend on itself.
  */
@@ -4134,6 +4267,61 @@ nghttp2_submit_priority(nghttp2_session *session, uint8_t flags,
                         const nghttp2_priority_spec *pri_spec);
 
 /**
+ * @macro
+ *
+ * :macro:`NGHTTP2_EXTPRI_DEFAULT_URGENCY` is the default urgency
+ * level for :rfc:`9218` extensible priorities.
+ */
+#define NGHTTP2_EXTPRI_DEFAULT_URGENCY 3
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP2_EXTPRI_URGENCY_HIGH` is the highest urgency level
+ * for :rfc:`9218` extensible priorities.
+ */
+#define NGHTTP2_EXTPRI_URGENCY_HIGH 0
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP2_EXTPRI_URGENCY_LOW` is the lowest urgency level for
+ * :rfc:`9218` extensible priorities.
+ */
+#define NGHTTP2_EXTPRI_URGENCY_LOW 7
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP2_EXTPRI_URGENCY_LEVELS` is the number of urgency
+ * levels for :rfc:`9218` extensible priorities.
+ */
+#define NGHTTP2_EXTPRI_URGENCY_LEVELS (NGHTTP2_EXTPRI_URGENCY_LOW + 1)
+
+/**
+ * @struct
+ *
+ * :type:`nghttp2_extpri` is :rfc:`9218` extensible priorities
+ * specification for a stream.
+ */
+typedef struct nghttp2_extpri {
+  /**
+   * :member:`urgency` is the urgency of a stream, it must be in
+   * [:macro:`NGHTTP2_EXTPRI_URGENCY_HIGH`,
+   * :macro:`NGHTTP2_EXTPRI_URGENCY_LOW`], inclusive, and 0 is the
+   * highest urgency.
+   */
+  uint32_t urgency;
+  /**
+   * :member:`inc` indicates that a content can be processed
+   * incrementally or not.  If inc is 0, it cannot be processed
+   * incrementally.  If inc is 1, it can be processed incrementally.
+   * Other value is not permitted.
+   */
+  int inc;
+} nghttp2_extpri;
+
+/**
  * @function
  *
  * Submits RST_STREAM frame to cancel/reject the stream |stream_id|
@@ -4142,14 +4330,14 @@ nghttp2_submit_priority(nghttp2_session *session, uint8_t flags,
  * The pre-defined error code is one of :enum:`nghttp2_error_code`.
  *
  * The |flags| is currently ignored and should be
- * :enum:`NGHTTP2_FLAG_NONE`.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0.
  */
 NGHTTP2_EXTERN int nghttp2_submit_rst_stream(nghttp2_session *session,
@@ -4164,7 +4352,7 @@ NGHTTP2_EXTERN int nghttp2_submit_rst_stream(nghttp2_session *session,
  * indicates the number of :type:`nghttp2_settings_entry`.
  *
  * The |flags| is currently ignored and should be
- * :enum:`NGHTTP2_FLAG_NONE`.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * This function does not take ownership of the |iv|.  This function
  * copies all the elements in the |iv|.
@@ -4173,16 +4361,17 @@ NGHTTP2_EXTERN int nghttp2_submit_rst_stream(nghttp2_session *session,
  * size becomes strictly larger than NGHTTP2_MAX_WINDOW_SIZE,
  * RST_STREAM is issued against such a stream.
  *
- * SETTINGS with :enum:`NGHTTP2_FLAG_ACK` is automatically submitted
- * by the library and application could not send it at its will.
+ * SETTINGS with :enum:`nghttp2_flag.NGHTTP2_FLAG_ACK` is
+ * automatically submitted by the library and application could not
+ * send it at its will.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |iv| contains invalid value (e.g., initial window size
  *     strictly greater than (1 << 31) - 1.
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_submit_settings(nghttp2_session *session,
@@ -4210,12 +4399,12 @@ NGHTTP2_EXTERN int nghttp2_submit_settings(nghttp2_session *session,
  * This function creates copies of all name/value pairs in |nva|.  It
  * also lower-cases all names in |nva|.  The order of elements in
  * |nva| is preserved.  For header fields with
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME` and
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set, header field name
- * and value are not copied respectively.  With
- * :enum:`NGHTTP2_NV_FLAG_NO_COPY_NAME`, application is responsible to
- * pass header field name in lowercase.  The application should
- * maintain the references to them until
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME` and
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set,
+ * header field name and value are not copied respectively.  With
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`, application
+ * is responsible to pass header field name in lowercase.  The
+ * application should maintain the references to them until
  * :type:`nghttp2_on_frame_send_callback` or
  * :type:`nghttp2_on_frame_not_send_callback` is called.
  *
@@ -4234,18 +4423,18 @@ NGHTTP2_EXTERN int nghttp2_submit_settings(nghttp2_session *session,
  * This function returns assigned promised stream ID if it succeeds,
  * or one of the following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_PROTO`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
  *     This function was invoked when |session| is initialized as
  *     client.
- * :enum:`NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE`
  *     No stream ID is available because maximum stream ID was
  *     reached.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is 0; The |stream_id| does not designate stream
  *     that peer initiated.
- * :enum:`NGHTTP2_ERR_STREAM_CLOSED`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_STREAM_CLOSED`
  *     The stream was already closed; or the |stream_id| is invalid.
  *
  * .. warning::
@@ -4274,10 +4463,10 @@ NGHTTP2_EXTERN int32_t nghttp2_submit_push_promise(
  *
  * The |flags| is bitwise OR of 0 or more of the following value.
  *
- * * :enum:`NGHTTP2_FLAG_ACK`
+ * * :enum:`nghttp2_flag.NGHTTP2_FLAG_ACK`
  *
  * Unless `nghttp2_option_set_no_auto_ping_ack()` is used, the |flags|
- * should be :enum:`NGHTTP2_FLAG_NONE`.
+ * should be :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * If the |opaque_data| is non ``NULL``, then it should point to the 8
  * bytes array of memory to specify opaque data to send with PING
@@ -4287,7 +4476,7 @@ NGHTTP2_EXTERN int32_t nghttp2_submit_push_promise(
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_submit_ping(nghttp2_session *session, uint8_t flags,
@@ -4302,7 +4491,7 @@ NGHTTP2_EXTERN int nghttp2_submit_ping(nghttp2_session *session, uint8_t flags,
  * The pre-defined error code is one of :enum:`nghttp2_error_code`.
  *
  * The |flags| is currently ignored and should be
- * :enum:`NGHTTP2_FLAG_NONE`.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * The |last_stream_id| is peer's stream ID or 0.  So if |session| is
  * initialized as client, |last_stream_id| must be even or 0.  If
@@ -4332,9 +4521,9 @@ NGHTTP2_EXTERN int nghttp2_submit_ping(nghttp2_session *session, uint8_t flags,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |opaque_data_len| is too large; the |last_stream_id| is
  *     invalid.
  */
@@ -4390,7 +4579,7 @@ nghttp2_session_check_server_session(nghttp2_session *session);
  * Submits WINDOW_UPDATE frame.
  *
  * The |flags| is currently ignored and should be
- * :enum:`NGHTTP2_FLAG_NONE`.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * The |stream_id| is the stream ID to send this WINDOW_UPDATE.  To
  * send connection level WINDOW_UPDATE, specify 0 to |stream_id|.
@@ -4417,9 +4606,9 @@ nghttp2_session_check_server_session(nghttp2_session *session);
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_FLOW_CONTROL`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_FLOW_CONTROL`
  *     The local window size overflow or gets negative.
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_submit_window_update(nghttp2_session *session,
@@ -4437,7 +4626,7 @@ NGHTTP2_EXTERN int nghttp2_submit_window_update(nghttp2_session *session,
  * to transmission queue.
  *
  * The |flags| is currently ignored and should be
- * :enum:`NGHTTP2_FLAG_NONE`.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * This sounds similar to `nghttp2_submit_window_update()`, but there
  * are 2 differences.  The first difference is that this function
@@ -4456,9 +4645,9 @@ NGHTTP2_EXTERN int nghttp2_submit_window_update(nghttp2_session *session,
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |stream_id| is negative.
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int
@@ -4489,18 +4678,19 @@ nghttp2_session_set_local_window_size(nghttp2_session *session, uint8_t flags,
  *
  * The standard HTTP/2 frame cannot be sent with this function, so
  * |type| must be strictly grater than 0x9.  Otherwise, this function
- * will fail with error code :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`.
+ * will fail with error code
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
  *     If :type:`nghttp2_pack_extension_callback` is not set.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     If  |type| specifies  standard  HTTP/2 frame  type.  The  frame
  *     types  in the  rage [0x0,  0x9], both  inclusive, are  standard
  *     HTTP/2 frame type, and cannot be sent using this function.
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory
  */
 NGHTTP2_EXTERN int nghttp2_submit_extension(nghttp2_session *session,
@@ -4514,8 +4704,8 @@ NGHTTP2_EXTERN int nghttp2_submit_extension(nghttp2_session *session,
  * extension to HTTP/2.  If this frame is received, and
  * `nghttp2_option_set_user_recv_extension_type()` is not set, and
  * `nghttp2_option_set_builtin_recv_extension_type()` is set for
- * :enum:`NGHTTP2_ALTSVC`, ``nghttp2_extension.payload`` will point to
- * this struct.
+ * :enum:`nghttp2_frame_type.NGHTTP2_ALTSVC`,
+ * ``nghttp2_extension.payload`` will point to this struct.
  *
  * It has the following members:
  */
@@ -4549,7 +4739,7 @@ typedef struct {
  * `RFC 7383 <https://tools.ietf.org/html/rfc7838#section-4>`_.
  *
  * The |flags| is currently ignored and should be
- * :enum:`NGHTTP2_FLAG_NONE`.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * The |origin| points to the origin this alternative service is
  * associated with.  The |origin_len| is the length of the origin.  If
@@ -4559,16 +4749,16 @@ typedef struct {
  *
  * The ALTSVC frame is only usable from server side.  If this function
  * is invoked with client side session, this function returns
- * :enum:`NGHTTP2_ERR_INVALID_STATE`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory
- * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
  *     The function is called from client side session
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The sum of |origin_len| and |field_value_len| is larger than
  *     16382; or |origin_len| is 0 while |stream_id| is 0; or
  *     |origin_len| is not 0 while |stream_id| is not 0.
@@ -4607,8 +4797,8 @@ typedef struct {
  * If this frame is received, and
  * `nghttp2_option_set_user_recv_extension_type()` is not set, and
  * `nghttp2_option_set_builtin_recv_extension_type()` is set for
- * :enum:`NGHTTP2_ORIGIN`, ``nghttp2_extension.payload`` will point to
- * this struct.
+ * :enum:`nghttp2_frame_type.NGHTTP2_ORIGIN`,
+ * ``nghttp2_extension.payload`` will point to this struct.
  *
  * It has the following members:
  */
@@ -4632,7 +4822,7 @@ typedef struct {
  * `RFC 8336 <https://tools.ietf.org/html/rfc8336>`_.
  *
  * The |flags| is currently ignored and should be
- * :enum:`NGHTTP2_FLAG_NONE`.
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
  * The |ov| points to the array of origins.  The |nov| specifies the
  * number of origins included in |ov|.  This function creates copies
@@ -4640,13 +4830,13 @@ typedef struct {
  *
  * The ORIGIN frame is only usable by a server.  If this function is
  * invoked with client side session, this function returns
- * :enum:`NGHTTP2_ERR_INVALID_STATE`.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`.
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory
- * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
  *     The function is called from client side session.
- * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     There are too many origins, or an origin is too large to fit
  *     into a default frame payload.
  */
@@ -4656,6 +4846,108 @@ NGHTTP2_EXTERN int nghttp2_submit_origin(nghttp2_session *session,
                                          size_t nov);
 
 /**
+ * @struct
+ *
+ * The payload of PRIORITY_UPDATE frame.  PRIORITY_UPDATE frame is a
+ * non-critical extension to HTTP/2.  If this frame is received, and
+ * `nghttp2_option_set_user_recv_extension_type()` is not set, and
+ * `nghttp2_option_set_builtin_recv_extension_type()` is set for
+ * :enum:`nghttp2_frame_type.NGHTTP2_PRIORITY_UPDATE`,
+ * ``nghttp2_extension.payload`` will point to this struct.
+ *
+ * It has the following members:
+ */
+typedef struct {
+  /**
+   * The stream ID of the stream whose priority is updated.
+   */
+  int32_t stream_id;
+  /**
+   * The pointer to Priority field value.  It is not necessarily
+   * NULL-terminated.
+   */
+  uint8_t *field_value;
+  /**
+   * The length of the :member:`field_value`.
+   */
+  size_t field_value_len;
+} nghttp2_ext_priority_update;
+
+/**
+ * @function
+ *
+ * Submits PRIORITY_UPDATE frame.
+ *
+ * PRIORITY_UPDATE frame is a non-critical extension to HTTP/2, and
+ * defined in :rfc:`9218#section-7.1`.
+ *
+ * The |flags| is currently ignored and should be
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
+ *
+ * The |stream_id| is the ID of stream which is prioritized.  The
+ * |field_value| points to the Priority field value.  The
+ * |field_value_len| is the length of the Priority field value.
+ *
+ * If this function is called by server,
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE` is returned.
+ *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 0 is received by a remote endpoint (or it is omitted),
+ * this function does nothing and returns 0.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
+ *     The function is called from server side session
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
+ *     The |field_value_len| is larger than 16380; or |stream_id| is
+ *     0.
+ */
+NGHTTP2_EXTERN int nghttp2_submit_priority_update(nghttp2_session *session,
+                                                  uint8_t flags,
+                                                  int32_t stream_id,
+                                                  const uint8_t *field_value,
+                                                  size_t field_value_len);
+
+/**
+ * @function
+ *
+ * Changes the priority of the existing stream denoted by |stream_id|.
+ * The new priority is |extpri|.  This function is meant to be used by
+ * server for :rfc:`9218` extensible prioritization scheme.
+ *
+ * If |session| is initialized as client, this function returns
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`.  For client, use
+ * `nghttp2_submit_priority_update()` instead.
+ *
+ * If :member:`extpri->urgency <nghttp2_extpri.urgency>` is out of
+ * bound, it is set to :macro:`NGHTTP2_EXTPRI_URGENCY_LOW`.
+ *
+ * If |ignore_client_signal| is nonzero, server starts to ignore
+ * client priority signals for this stream.
+ *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 1 is not submitted via `nghttp2_submit_settings()`,
+ * this function does nothing and returns 0.
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
+ *     The |session| is initialized as client.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
+ *     |stream_id| is zero; or a stream denoted by |stream_id| is not
+ *     found.
+ */
+NGHTTP2_EXTERN int nghttp2_session_change_extpri_stream_priority(
+    nghttp2_session *session, int32_t stream_id, const nghttp2_extpri *extpri,
+    int ignore_client_signal);
+
+/**
  * @function
  *
  * Compares ``lhs->name`` of length ``lhs->namelen`` bytes and
@@ -4766,13 +5058,51 @@ NGHTTP2_EXTERN int nghttp2_check_header_name(const uint8_t *name, size_t len);
  * Returns nonzero if HTTP header field value |value| of length |len|
  * is valid according to
  * http://tools.ietf.org/html/rfc7230#section-3.2
+ *
+ * This function is considered obsolete, and application should
+ * consider to use `nghttp2_check_header_value_rfc9113()` instead.
  */
 NGHTTP2_EXTERN int nghttp2_check_header_value(const uint8_t *value, size_t len);
 
 /**
  * @function
  *
- * Returns nonzero if the |value| which is supposed to the value of
+ * Returns nonzero if HTTP header field value |value| of length |len|
+ * is valid according to
+ * http://tools.ietf.org/html/rfc7230#section-3.2, plus
+ * https://datatracker.ietf.org/doc/html/rfc9113#section-8.2.1
+ */
+NGHTTP2_EXTERN int nghttp2_check_header_value_rfc9113(const uint8_t *value,
+                                                      size_t len);
+
+/**
+ * @function
+ *
+ * Returns nonzero if the |value| which is supposed to be the value of
+ * the :method header field is valid according to
+ * https://datatracker.ietf.org/doc/html/rfc7231#section-4 and
+ * https://datatracker.ietf.org/doc/html/rfc7230#section-3.2.6
+ */
+NGHTTP2_EXTERN int nghttp2_check_method(const uint8_t *value, size_t len);
+
+/**
+ * @function
+ *
+ * Returns nonzero if the |value| which is supposed to be the value of
+ * the :path header field is valid according to
+ * https://datatracker.ietf.org/doc/html/rfc7540#section-8.1.2.3
+ *
+ * |value| is valid if it merely consists of the allowed characters.
+ * In particular, it does not check whether |value| follows the syntax
+ * of path.  The allowed characters are all characters valid by
+ * `nghttp2_check_header_value` minus SPC and HT.
+ */
+NGHTTP2_EXTERN int nghttp2_check_path(const uint8_t *value, size_t len);
+
+/**
+ * @function
+ *
+ * Returns nonzero if the |value| which is supposed to be the value of the
  * :authority or host header field is valid according to
  * https://tools.ietf.org/html/rfc3986#section-3.2
  *
@@ -4806,7 +5136,7 @@ typedef struct nghttp2_hd_deflater nghttp2_hd_deflater;
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int
@@ -4860,7 +5190,7 @@ NGHTTP2_EXTERN void nghttp2_hd_deflate_del(nghttp2_hd_deflater *deflater);
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int
@@ -4874,24 +5204,24 @@ nghttp2_hd_deflate_change_table_size(nghttp2_hd_deflater *deflater,
  * the |buf| of length |buflen|.
  *
  * If |buf| is not large enough to store the deflated header block,
- * this function fails with :enum:`NGHTTP2_ERR_INSUFF_BUFSIZE`.  The
- * caller should use `nghttp2_hd_deflate_bound()` to know the upper
- * bound of buffer size required to deflate given header name/value
- * pairs.
+ * this function fails with
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`.  The caller
+ * should use `nghttp2_hd_deflate_bound()` to know the upper bound of
+ * buffer size required to deflate given header name/value pairs.
  *
  * Once this function fails, subsequent call of this function always
- * returns :enum:`NGHTTP2_ERR_HEADER_COMP`.
+ * returns :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`.
  *
  * After this function returns, it is safe to delete the |nva|.
  *
  * This function returns the number of bytes written to |buf| if it
  * succeeds, or one of the following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_HEADER_COMP`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`
  *     Deflation process has failed.
- * :enum:`NGHTTP2_ERR_INSUFF_BUFSIZE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`
  *     The provided |buflen| size is too small to hold the output.
  */
 NGHTTP2_EXTERN ssize_t nghttp2_hd_deflate_hd(nghttp2_hd_deflater *deflater,
@@ -4907,23 +5237,24 @@ NGHTTP2_EXTERN ssize_t nghttp2_hd_deflate_hd(nghttp2_hd_deflater *deflater,
  * must be set in len field of :type:`nghttp2_vec`.  If and only if
  * one chunk is filled up completely, next chunk will be used.  If
  * |vec| is not large enough to store the deflated header block, this
- * function fails with :enum:`NGHTTP2_ERR_INSUFF_BUFSIZE`.  The caller
+ * function fails with
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`.  The caller
  * should use `nghttp2_hd_deflate_bound()` to know the upper bound of
  * buffer size required to deflate given header name/value pairs.
  *
  * Once this function fails, subsequent call of this function always
- * returns :enum:`NGHTTP2_ERR_HEADER_COMP`.
+ * returns :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`.
  *
  * After this function returns, it is safe to delete the |nva|.
  *
  * This function returns the number of bytes written to |vec| if it
  * succeeds, or one of the following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_HEADER_COMP`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`
  *     Deflation process has failed.
- * :enum:`NGHTTP2_ERR_INSUFF_BUFSIZE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`
  *     The provided |buflen| size is too small to hold the output.
  */
 NGHTTP2_EXTERN ssize_t nghttp2_hd_deflate_hd_vec(nghttp2_hd_deflater *deflater,
@@ -5003,7 +5334,7 @@ typedef struct nghttp2_hd_inflater nghttp2_hd_inflater;
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
 NGHTTP2_EXTERN int nghttp2_hd_inflate_new(nghttp2_hd_inflater **inflater_ptr);
@@ -5052,9 +5383,9 @@ NGHTTP2_EXTERN void nghttp2_hd_inflate_del(nghttp2_hd_inflater *inflater);
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
  *     The function is called while header block is being inflated.
  *     Probably, application missed to call
  *     `nghttp2_hd_inflate_end_headers()`.
@@ -5092,7 +5423,8 @@ typedef enum {
  *
  * Inflates name/value block stored in |in| with length |inlen|.  This
  * function performs decompression.  For each successful emission of
- * header name/value pair, :enum:`NGHTTP2_HD_INFLATE_EMIT` is set in
+ * header name/value pair,
+ * :enum:`nghttp2_hd_inflate_flag.NGHTTP2_HD_INFLATE_EMIT` is set in
  * |*inflate_flags| and name/value pair is assigned to the |nv_out|
  * and the function returns.  The caller must not free the members of
  * |nv_out|.
@@ -5115,11 +5447,11 @@ typedef enum {
  * This function returns the number of bytes processed if it succeeds,
  * or one of the following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_HEADER_COMP`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`
  *     Inflation process has failed.
- * :enum:`NGHTTP2_ERR_BUFFER_ERROR`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_BUFFER_ERROR`
  *     The header field name or value is too large.
  *
  * Example follows::
@@ -5174,7 +5506,8 @@ NGHTTP2_EXTERN ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_inflater *inflater,
  *
  * Inflates name/value block stored in |in| with length |inlen|.  This
  * function performs decompression.  For each successful emission of
- * header name/value pair, :enum:`NGHTTP2_HD_INFLATE_EMIT` is set in
+ * header name/value pair,
+ * :enum:`nghttp2_hd_inflate_flag.NGHTTP2_HD_INFLATE_EMIT` is set in
  * |*inflate_flags| and name/value pair is assigned to the |nv_out|
  * and the function returns.  The caller must not free the members of
  * |nv_out|.
@@ -5190,8 +5523,9 @@ NGHTTP2_EXTERN ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_inflater *inflater,
  * for the next header block input.
  *
  * In other words, if |in_final| is nonzero, and this function returns
- * |inlen|, you can assert that :enum:`NGHTTP2_HD_INFLATE_FINAL` is
- * set in |*inflate_flags|.
+ * |inlen|, you can assert that
+ * :enum:`nghttp2_hd_inflate_final.NGHTTP2_HD_INFLATE_FINAL` is set in
+ * |*inflate_flags|.
  *
  * The caller can feed complete compressed header block.  It also can
  * feed it in several chunks.  The caller must set |in_final| to
@@ -5201,11 +5535,11 @@ NGHTTP2_EXTERN ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_inflater *inflater,
  * This function returns the number of bytes processed if it succeeds,
  * or one of the following negative error codes:
  *
- * :enum:`NGHTTP2_ERR_NOMEM`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_HEADER_COMP`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`
  *     Inflation process has failed.
- * :enum:`NGHTTP2_ERR_BUFFER_ERROR`
+ * :enum:`nghttp2_error.NGHTTP2_ERR_BUFFER_ERROR`
  *     The header field name or value is too large.
  *
  * Example follows::
@@ -5376,7 +5710,7 @@ typedef enum {
  *
  * Returns state of |stream|.  The root stream retrieved by
  * `nghttp2_session_get_root_stream()` will have stream state
- * :enum:`NGHTTP2_STREAM_STATE_IDLE`.
+ * :enum:`nghttp2_stream_proto_state.NGHTTP2_STREAM_STATE_IDLE`.
  */
 NGHTTP2_EXTERN nghttp2_stream_proto_state
 nghttp2_stream_get_state(nghttp2_stream *stream);
diff --git a/Utilities/cmnghttp2/lib/nghttp2_buf.c b/Utilities/cmnghttp2/lib/nghttp2_buf.c
index 2a435bebf9..a32844712e 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_buf.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_buf.c
@@ -82,8 +82,10 @@ void nghttp2_buf_reset(nghttp2_buf *buf) {
 }
 
 void nghttp2_buf_wrap_init(nghttp2_buf *buf, uint8_t *begin, size_t len) {
-  buf->begin = buf->pos = buf->last = buf->mark = begin;
-  buf->end = begin + len;
+  buf->begin = buf->pos = buf->last = buf->mark = buf->end = begin;
+  if (len) {
+    buf->end += len;
+  }
 }
 
 static int buf_chain_new(nghttp2_buf_chain **chain, size_t chunk_length,
diff --git a/Utilities/cmnghttp2/lib/nghttp2_buf.h b/Utilities/cmnghttp2/lib/nghttp2_buf.h
index 06cce67a11..45f62f16e2 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_buf.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_buf.h
@@ -99,7 +99,7 @@ void nghttp2_buf_free(nghttp2_buf *buf, nghttp2_mem *mem);
  * |new_cap|. If extensions took place, buffer pointers in |buf| will
  * change.
  *
- * This function returns 0 if it succeeds, or one of the followings
+ * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
  * NGHTTP2_ERR_NOMEM
diff --git a/Utilities/cmnghttp2/lib/nghttp2_extpri.c b/Utilities/cmnghttp2/lib/nghttp2_extpri.c
new file mode 100644
index 0000000000..3fd9b78163
--- /dev/null
+++ b/Utilities/cmnghttp2/lib/nghttp2_extpri.c
@@ -0,0 +1,35 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2022 nghttp3 contributors
+ * Copyright (c) 2022 nghttp2 contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include "nghttp2_extpri.h"
+
+uint8_t nghttp2_extpri_to_uint8(const nghttp2_extpri *extpri) {
+  return (uint8_t)((uint32_t)extpri->inc << 7 | extpri->urgency);
+}
+
+void nghttp2_extpri_from_uint8(nghttp2_extpri *extpri, uint8_t u8extpri) {
+  extpri->urgency = nghttp2_extpri_uint8_urgency(u8extpri);
+  extpri->inc = nghttp2_extpri_uint8_inc(u8extpri);
+}
diff --git a/Utilities/cmnghttp2/lib/nghttp2_extpri.h b/Utilities/cmnghttp2/lib/nghttp2_extpri.h
new file mode 100644
index 0000000000..23c6ddc0c0
--- /dev/null
+++ b/Utilities/cmnghttp2/lib/nghttp2_extpri.h
@@ -0,0 +1,65 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2022 nghttp3 contributors
+ * Copyright (c) 2022 nghttp2 contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef NGHTTP2_EXTPRI_H
+#define NGHTTP2_EXTPRI_H
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#include <nghttp2/nghttp2.h>
+
+/*
+ * NGHTTP2_EXTPRI_INC_MASK is a bit mask to retrieve incremental bit
+ * from a value produced by nghttp2_extpri_to_uint8.
+ */
+#define NGHTTP2_EXTPRI_INC_MASK (1 << 7)
+
+/*
+ * nghttp2_extpri_to_uint8 encodes |pri| into uint8_t variable.
+ */
+uint8_t nghttp2_extpri_to_uint8(const nghttp2_extpri *extpri);
+
+/*
+ * nghttp2_extpri_from_uint8 decodes |u8extpri|, which is produced by
+ * nghttp2_extpri_to_uint8, intto |extpri|.
+ */
+void nghttp2_extpri_from_uint8(nghttp2_extpri *extpri, uint8_t u8extpri);
+
+/*
+ * nghttp2_extpri_uint8_urgency extracts urgency from |PRI| which is
+ * supposed to be constructed by nghttp2_extpri_to_uint8.
+ */
+#define nghttp2_extpri_uint8_urgency(PRI)                                      \
+  ((uint32_t)((PRI) & ~NGHTTP2_EXTPRI_INC_MASK))
+
+/*
+ * nghttp2_extpri_uint8_inc extracts inc from |PRI| which is supposed to
+ * be constructed by nghttp2_extpri_to_uint8.
+ */
+#define nghttp2_extpri_uint8_inc(PRI) (((PRI)&NGHTTP2_EXTPRI_INC_MASK) != 0)
+
+#endif /* NGHTTP2_EXTPRI_H */
diff --git a/Utilities/cmnghttp2/lib/nghttp2_frame.c b/Utilities/cmnghttp2/lib/nghttp2_frame.c
index 4821de4088..35072c15fc 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_frame.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_frame.c
@@ -253,6 +253,31 @@ void nghttp2_frame_origin_free(nghttp2_extension *frame, nghttp2_mem *mem) {
   nghttp2_mem_free(mem, origin->ov);
 }
 
+void nghttp2_frame_priority_update_init(nghttp2_extension *frame,
+                                        int32_t stream_id, uint8_t *field_value,
+                                        size_t field_value_len) {
+  nghttp2_ext_priority_update *priority_update;
+
+  nghttp2_frame_hd_init(&frame->hd, 4 + field_value_len,
+                        NGHTTP2_PRIORITY_UPDATE, NGHTTP2_FLAG_NONE, 0);
+
+  priority_update = frame->payload;
+  priority_update->stream_id = stream_id;
+  priority_update->field_value = field_value;
+  priority_update->field_value_len = field_value_len;
+}
+
+void nghttp2_frame_priority_update_free(nghttp2_extension *frame,
+                                        nghttp2_mem *mem) {
+  nghttp2_ext_priority_update *priority_update;
+
+  priority_update = frame->payload;
+  if (priority_update == NULL) {
+    return;
+  }
+  nghttp2_mem_free(mem, priority_update->field_value);
+}
+
 size_t nghttp2_frame_priority_len(uint8_t flags) {
   if (flags & NGHTTP2_FLAG_PRIORITY) {
     return NGHTTP2_PRIORITY_SPECLEN;
@@ -654,8 +679,6 @@ int nghttp2_frame_unpack_goaway_payload2(nghttp2_goaway *frame,
     var_gift_payloadlen = 0;
   }
 
-  payloadlen -= var_gift_payloadlen;
-
   if (!var_gift_payloadlen) {
     var_gift_payload = NULL;
   } else {
@@ -818,8 +841,10 @@ int nghttp2_frame_unpack_origin_payload(nghttp2_extension *frame,
   size_t len = 0;
 
   origin = frame->payload;
-  p = payload;
-  end = p + payloadlen;
+  p = end = payload;
+  if (payloadlen) {
+    end += payloadlen;
+  }
 
   for (; p != end;) {
     if (end - p < 2) {
@@ -876,6 +901,57 @@ int nghttp2_frame_unpack_origin_payload(nghttp2_extension *frame,
   return 0;
 }
 
+int nghttp2_frame_pack_priority_update(nghttp2_bufs *bufs,
+                                       nghttp2_extension *frame) {
+  int rv;
+  nghttp2_buf *buf;
+  nghttp2_ext_priority_update *priority_update;
+
+  /* This is required with --disable-assert. */
+  (void)rv;
+
+  priority_update = frame->payload;
+
+  buf = &bufs->head->buf;
+
+  assert(nghttp2_buf_avail(buf) >= 4 + priority_update->field_value_len);
+
+  buf->pos -= NGHTTP2_FRAME_HDLEN;
+
+  nghttp2_frame_pack_frame_hd(buf->pos, &frame->hd);
+
+  nghttp2_put_uint32be(buf->last, (uint32_t)priority_update->stream_id);
+  buf->last += 4;
+
+  rv = nghttp2_bufs_add(bufs, priority_update->field_value,
+                        priority_update->field_value_len);
+
+  assert(rv == 0);
+
+  return 0;
+}
+
+void nghttp2_frame_unpack_priority_update_payload(nghttp2_extension *frame,
+                                                  uint8_t *payload,
+                                                  size_t payloadlen) {
+  nghttp2_ext_priority_update *priority_update;
+
+  assert(payloadlen >= 4);
+
+  priority_update = frame->payload;
+
+  priority_update->stream_id =
+      nghttp2_get_uint32(payload) & NGHTTP2_STREAM_ID_MASK;
+
+  if (payloadlen > 4) {
+    priority_update->field_value = payload + 4;
+    priority_update->field_value_len = payloadlen - 4;
+  } else {
+    priority_update->field_value = NULL;
+    priority_update->field_value_len = 0;
+  }
+}
+
 nghttp2_settings_entry *nghttp2_frame_iv_copy(const nghttp2_settings_entry *iv,
                                               size_t niv, nghttp2_mem *mem) {
   nghttp2_settings_entry *iv_copy;
@@ -897,9 +973,25 @@ nghttp2_settings_entry *nghttp2_frame_iv_copy(const nghttp2_settings_entry *iv,
 }
 
 int nghttp2_nv_equal(const nghttp2_nv *a, const nghttp2_nv *b) {
-  return a->namelen == b->namelen && a->valuelen == b->valuelen &&
-         memcmp(a->name, b->name, a->namelen) == 0 &&
-         memcmp(a->value, b->value, a->valuelen) == 0;
+  if (a->namelen != b->namelen || a->valuelen != b->valuelen) {
+    return 0;
+  }
+
+  if (a->name == NULL || b->name == NULL) {
+    assert(a->namelen == 0);
+    assert(b->namelen == 0);
+  } else if (memcmp(a->name, b->name, a->namelen) != 0) {
+    return 0;
+  }
+
+  if (a->value == NULL || b->value == NULL) {
+    assert(a->valuelen == 0);
+    assert(b->valuelen == 0);
+  } else if (memcmp(a->value, b->value, a->valuelen) != 0) {
+    return 0;
+  }
+
+  return 1;
 }
 
 void nghttp2_nv_array_del(nghttp2_nv *nva, nghttp2_mem *mem) {
@@ -1055,6 +1147,11 @@ int nghttp2_iv_check(const nghttp2_settings_entry *iv, size_t niv) {
         return 0;
       }
       break;
+    case NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES:
+      if (iv[i].value != 0 && iv[i].value != 1) {
+        return 0;
+      }
+      break;
     }
   }
   return 1;
diff --git a/Utilities/cmnghttp2/lib/nghttp2_frame.h b/Utilities/cmnghttp2/lib/nghttp2_frame.h
index 615bbf31f5..5f6152b745 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_frame.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_frame.h
@@ -46,7 +46,7 @@
 #define NGHTTP2_MAX_FRAME_SIZE_MIN (1 << 14)
 
 #define NGHTTP2_MAX_PAYLOADLEN 16384
-/* The one frame buffer length for tranmission.  We may use several of
+/* The one frame buffer length for transmission.  We may use several of
    them to support CONTINUATION.  To account for Pad Length field, we
    allocate extra 1 byte, which saves extra large memcopying. */
 #define NGHTTP2_FRAMEBUF_CHUNKLEN                                              \
@@ -57,7 +57,7 @@
 
 /* Maximum headers block size to send, calculated using
    nghttp2_hd_deflate_bound().  This is the default value, and can be
-   overridden by nghttp2_option_set_max_send_header_block_size(). */
+   overridden by nghttp2_option_set_max_send_header_block_length(). */
 #define NGHTTP2_MAX_HEADERSLEN 65536
 
 /* The number of bytes for each SETTINGS entry */
@@ -73,6 +73,7 @@
 typedef union {
   nghttp2_ext_altsvc altsvc;
   nghttp2_ext_origin origin;
+  nghttp2_ext_priority_update priority_update;
 } nghttp2_ext_frame_payload;
 
 void nghttp2_frame_pack_frame_hd(uint8_t *buf, const nghttp2_frame_hd *hd);
@@ -423,6 +424,31 @@ int nghttp2_frame_pack_origin(nghttp2_bufs *bufs, nghttp2_extension *ext);
 int nghttp2_frame_unpack_origin_payload(nghttp2_extension *frame,
                                         const uint8_t *payload,
                                         size_t payloadlen, nghttp2_mem *mem);
+
+/*
+ * Packs PRIORITY_UPDATE frame |frame| in wire frame format and store
+ * it in |bufs|.
+ *
+ * The caller must make sure that nghttp2_bufs_reset(bufs) is called
+ * before calling this function.
+ *
+ * This function always succeeds and returns 0.
+ */
+int nghttp2_frame_pack_priority_update(nghttp2_bufs *bufs,
+                                       nghttp2_extension *ext);
+
+/*
+ * Unpacks PRIORITY_UPDATE wire format into |frame|.  The |payload| of
+ * |payloadlen| bytes contains frame payload.  This function assumes
+ * that frame->payload points to the nghttp2_ext_priority_update
+ * object.
+ *
+ * This function always succeeds and returns 0.
+ */
+void nghttp2_frame_unpack_priority_update_payload(nghttp2_extension *frame,
+                                                  uint8_t *payload,
+                                                  size_t payloadlen);
+
 /*
  * Initializes HEADERS frame |frame| with given values.  |frame| takes
  * ownership of |nva|, so caller must not free it. If |stream_id| is
@@ -539,6 +565,25 @@ void nghttp2_frame_origin_init(nghttp2_extension *frame,
 void nghttp2_frame_origin_free(nghttp2_extension *frame, nghttp2_mem *mem);
 
 /*
+ * Initializes PRIORITY_UPDATE frame |frame| with given values.  This
+ * function assumes that frame->payload points to
+ * nghttp2_ext_priority_update object.  On success, this function
+ * takes ownership of |field_value|, so caller must not free it.
+ */
+void nghttp2_frame_priority_update_init(nghttp2_extension *frame,
+                                        int32_t stream_id, uint8_t *field_value,
+                                        size_t field_value_len);
+
+/*
+ * Frees up resources under |frame|.  This function does not free
+ * nghttp2_ext_priority_update object pointed by frame->payload.  This
+ * function only frees field_value pointed by
+ * nghttp2_ext_priority_update.field_value.
+ */
+void nghttp2_frame_priority_update_free(nghttp2_extension *frame,
+                                        nghttp2_mem *mem);
+
+/*
  * Returns the number of padding bytes after payload.  The total
  * padding length is given in the |padlen|.  The returned value does
  * not include the Pad Length field.  If |padlen| is 0, this function
diff --git a/Utilities/cmnghttp2/lib/nghttp2_hd.c b/Utilities/cmnghttp2/lib/nghttp2_hd.c
index 5e86931525..8a2bda64c1 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_hd.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_hd.c
@@ -269,6 +269,11 @@ static int32_t lookup_token(const uint8_t *name, size_t namelen) {
         return NGHTTP2_TOKEN_LOCATION;
       }
       break;
+    case 'y':
+      if (memeq("priorit", name, 7)) {
+        return NGHTTP2_TOKEN_PRIORITY;
+      }
+      break;
     }
     break;
   case 9:
@@ -1263,6 +1268,8 @@ int nghttp2_hd_inflate_change_table_size(
     return NGHTTP2_ERR_INVALID_STATE;
   }
 
+  inflater->settings_hd_table_bufsize_max = settings_max_dynamic_table_size;
+
   /* It seems that encoder is not required to send dynamic table size
      update if the table size is not changed after applying
      SETTINGS_HEADER_TABLE_SIZE.  RFC 7541 is ambiguous here, but this
@@ -1275,13 +1282,12 @@ int nghttp2_hd_inflate_change_table_size(
     /* Remember minimum value, and validate that encoder sends the
        value less than or equal to this. */
     inflater->min_hd_table_bufsize_max = settings_max_dynamic_table_size;
-  }
 
-  inflater->settings_hd_table_bufsize_max = settings_max_dynamic_table_size;
+    inflater->ctx.hd_table_bufsize_max = settings_max_dynamic_table_size;
 
-  inflater->ctx.hd_table_bufsize_max = settings_max_dynamic_table_size;
+    hd_context_shrink_table_size(&inflater->ctx, NULL);
+  }
 
-  hd_context_shrink_table_size(&inflater->ctx, NULL);
   return 0;
 }
 
diff --git a/Utilities/cmnghttp2/lib/nghttp2_hd.h b/Utilities/cmnghttp2/lib/nghttp2_hd.h
index 267402881f..6de0052aae 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_hd.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_hd.h
@@ -112,6 +112,7 @@ typedef enum {
   NGHTTP2_TOKEN_PROXY_CONNECTION,
   NGHTTP2_TOKEN_UPGRADE,
   NGHTTP2_TOKEN__PROTOCOL,
+  NGHTTP2_TOKEN_PRIORITY,
 } nghttp2_token;
 
 struct nghttp2_hd_entry;
diff --git a/Utilities/cmnghttp2/lib/nghttp2_helper.c b/Utilities/cmnghttp2/lib/nghttp2_helper.c
index 91136a6198..93dd4754b7 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_helper.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_helper.c
@@ -334,6 +334,8 @@ const char *nghttp2_strerror(int error_code) {
   case NGHTTP2_ERR_FLOODED:
     return "Flooding was detected in this HTTP/2 session, and it must be "
            "closed";
+  case NGHTTP2_ERR_TOO_MANY_SETTINGS:
+    return "SETTINGS frame contained more than the maximum allowed entries";
   default:
     return "Unknown error code";
   }
@@ -505,7 +507,179 @@ int nghttp2_check_header_value(const uint8_t *value, size_t len) {
   return 1;
 }
 
-/* Generated by genauthroitychartbl.py */
+int nghttp2_check_header_value_rfc9113(const uint8_t *value, size_t len) {
+  if (len == 0) {
+    return 1;
+  }
+
+  if (*value == ' ' || *value == '\t' || *(value + len - 1) == ' ' ||
+      *(value + len - 1) == '\t') {
+    return 0;
+  }
+
+  return nghttp2_check_header_value(value, len);
+}
+
+/* Generated by genmethodchartbl.py */
+static char VALID_METHOD_CHARS[] = {
+    0 /* NUL  */, 0 /* SOH  */, 0 /* STX  */, 0 /* ETX  */,
+    0 /* EOT  */, 0 /* ENQ  */, 0 /* ACK  */, 0 /* BEL  */,
+    0 /* BS   */, 0 /* HT   */, 0 /* LF   */, 0 /* VT   */,
+    0 /* FF   */, 0 /* CR   */, 0 /* SO   */, 0 /* SI   */,
+    0 /* DLE  */, 0 /* DC1  */, 0 /* DC2  */, 0 /* DC3  */,
+    0 /* DC4  */, 0 /* NAK  */, 0 /* SYN  */, 0 /* ETB  */,
+    0 /* CAN  */, 0 /* EM   */, 0 /* SUB  */, 0 /* ESC  */,
+    0 /* FS   */, 0 /* GS   */, 0 /* RS   */, 0 /* US   */,
+    0 /* SPC  */, 1 /* !    */, 0 /* "    */, 1 /* #    */,
+    1 /* $    */, 1 /* %    */, 1 /* &    */, 1 /* '    */,
+    0 /* (    */, 0 /* )    */, 1 /* *    */, 1 /* +    */,
+    0 /* ,    */, 1 /* -    */, 1 /* .    */, 0 /* /    */,
+    1 /* 0    */, 1 /* 1    */, 1 /* 2    */, 1 /* 3    */,
+    1 /* 4    */, 1 /* 5    */, 1 /* 6    */, 1 /* 7    */,
+    1 /* 8    */, 1 /* 9    */, 0 /* :    */, 0 /* ;    */,
+    0 /* <    */, 0 /* =    */, 0 /* >    */, 0 /* ?    */,
+    0 /* @    */, 1 /* A    */, 1 /* B    */, 1 /* C    */,
+    1 /* D    */, 1 /* E    */, 1 /* F    */, 1 /* G    */,
+    1 /* H    */, 1 /* I    */, 1 /* J    */, 1 /* K    */,
+    1 /* L    */, 1 /* M    */, 1 /* N    */, 1 /* O    */,
+    1 /* P    */, 1 /* Q    */, 1 /* R    */, 1 /* S    */,
+    1 /* T    */, 1 /* U    */, 1 /* V    */, 1 /* W    */,
+    1 /* X    */, 1 /* Y    */, 1 /* Z    */, 0 /* [    */,
+    0 /* \    */, 0 /* ]    */, 1 /* ^    */, 1 /* _    */,
+    1 /* `    */, 1 /* a    */, 1 /* b    */, 1 /* c    */,
+    1 /* d    */, 1 /* e    */, 1 /* f    */, 1 /* g    */,
+    1 /* h    */, 1 /* i    */, 1 /* j    */, 1 /* k    */,
+    1 /* l    */, 1 /* m    */, 1 /* n    */, 1 /* o    */,
+    1 /* p    */, 1 /* q    */, 1 /* r    */, 1 /* s    */,
+    1 /* t    */, 1 /* u    */, 1 /* v    */, 1 /* w    */,
+    1 /* x    */, 1 /* y    */, 1 /* z    */, 0 /* {    */,
+    1 /* |    */, 0 /* }    */, 1 /* ~    */, 0 /* DEL  */,
+    0 /* 0x80 */, 0 /* 0x81 */, 0 /* 0x82 */, 0 /* 0x83 */,
+    0 /* 0x84 */, 0 /* 0x85 */, 0 /* 0x86 */, 0 /* 0x87 */,
+    0 /* 0x88 */, 0 /* 0x89 */, 0 /* 0x8a */, 0 /* 0x8b */,
+    0 /* 0x8c */, 0 /* 0x8d */, 0 /* 0x8e */, 0 /* 0x8f */,
+    0 /* 0x90 */, 0 /* 0x91 */, 0 /* 0x92 */, 0 /* 0x93 */,
+    0 /* 0x94 */, 0 /* 0x95 */, 0 /* 0x96 */, 0 /* 0x97 */,
+    0 /* 0x98 */, 0 /* 0x99 */, 0 /* 0x9a */, 0 /* 0x9b */,
+    0 /* 0x9c */, 0 /* 0x9d */, 0 /* 0x9e */, 0 /* 0x9f */,
+    0 /* 0xa0 */, 0 /* 0xa1 */, 0 /* 0xa2 */, 0 /* 0xa3 */,
+    0 /* 0xa4 */, 0 /* 0xa5 */, 0 /* 0xa6 */, 0 /* 0xa7 */,
+    0 /* 0xa8 */, 0 /* 0xa9 */, 0 /* 0xaa */, 0 /* 0xab */,
+    0 /* 0xac */, 0 /* 0xad */, 0 /* 0xae */, 0 /* 0xaf */,
+    0 /* 0xb0 */, 0 /* 0xb1 */, 0 /* 0xb2 */, 0 /* 0xb3 */,
+    0 /* 0xb4 */, 0 /* 0xb5 */, 0 /* 0xb6 */, 0 /* 0xb7 */,
+    0 /* 0xb8 */, 0 /* 0xb9 */, 0 /* 0xba */, 0 /* 0xbb */,
+    0 /* 0xbc */, 0 /* 0xbd */, 0 /* 0xbe */, 0 /* 0xbf */,
+    0 /* 0xc0 */, 0 /* 0xc1 */, 0 /* 0xc2 */, 0 /* 0xc3 */,
+    0 /* 0xc4 */, 0 /* 0xc5 */, 0 /* 0xc6 */, 0 /* 0xc7 */,
+    0 /* 0xc8 */, 0 /* 0xc9 */, 0 /* 0xca */, 0 /* 0xcb */,
+    0 /* 0xcc */, 0 /* 0xcd */, 0 /* 0xce */, 0 /* 0xcf */,
+    0 /* 0xd0 */, 0 /* 0xd1 */, 0 /* 0xd2 */, 0 /* 0xd3 */,
+    0 /* 0xd4 */, 0 /* 0xd5 */, 0 /* 0xd6 */, 0 /* 0xd7 */,
+    0 /* 0xd8 */, 0 /* 0xd9 */, 0 /* 0xda */, 0 /* 0xdb */,
+    0 /* 0xdc */, 0 /* 0xdd */, 0 /* 0xde */, 0 /* 0xdf */,
+    0 /* 0xe0 */, 0 /* 0xe1 */, 0 /* 0xe2 */, 0 /* 0xe3 */,
+    0 /* 0xe4 */, 0 /* 0xe5 */, 0 /* 0xe6 */, 0 /* 0xe7 */,
+    0 /* 0xe8 */, 0 /* 0xe9 */, 0 /* 0xea */, 0 /* 0xeb */,
+    0 /* 0xec */, 0 /* 0xed */, 0 /* 0xee */, 0 /* 0xef */,
+    0 /* 0xf0 */, 0 /* 0xf1 */, 0 /* 0xf2 */, 0 /* 0xf3 */,
+    0 /* 0xf4 */, 0 /* 0xf5 */, 0 /* 0xf6 */, 0 /* 0xf7 */,
+    0 /* 0xf8 */, 0 /* 0xf9 */, 0 /* 0xfa */, 0 /* 0xfb */,
+    0 /* 0xfc */, 0 /* 0xfd */, 0 /* 0xfe */, 0 /* 0xff */
+};
+
+int nghttp2_check_method(const uint8_t *value, size_t len) {
+  const uint8_t *last;
+  if (len == 0) {
+    return 0;
+  }
+  for (last = value + len; value != last; ++value) {
+    if (!VALID_METHOD_CHARS[*value]) {
+      return 0;
+    }
+  }
+  return 1;
+}
+
+/* Generated by genpathchartbl.py */
+static char VALID_PATH_CHARS[] = {
+    0 /* NUL  */, 0 /* SOH  */, 0 /* STX  */, 0 /* ETX  */,
+    0 /* EOT  */, 0 /* ENQ  */, 0 /* ACK  */, 0 /* BEL  */,
+    0 /* BS   */, 0 /* HT   */, 0 /* LF   */, 0 /* VT   */,
+    0 /* FF   */, 0 /* CR   */, 0 /* SO   */, 0 /* SI   */,
+    0 /* DLE  */, 0 /* DC1  */, 0 /* DC2  */, 0 /* DC3  */,
+    0 /* DC4  */, 0 /* NAK  */, 0 /* SYN  */, 0 /* ETB  */,
+    0 /* CAN  */, 0 /* EM   */, 0 /* SUB  */, 0 /* ESC  */,
+    0 /* FS   */, 0 /* GS   */, 0 /* RS   */, 0 /* US   */,
+    0 /* SPC  */, 1 /* !    */, 1 /* "    */, 1 /* #    */,
+    1 /* $    */, 1 /* %    */, 1 /* &    */, 1 /* '    */,
+    1 /* (    */, 1 /* )    */, 1 /* *    */, 1 /* +    */,
+    1 /* ,    */, 1 /* -    */, 1 /* .    */, 1 /* /    */,
+    1 /* 0    */, 1 /* 1    */, 1 /* 2    */, 1 /* 3    */,
+    1 /* 4    */, 1 /* 5    */, 1 /* 6    */, 1 /* 7    */,
+    1 /* 8    */, 1 /* 9    */, 1 /* :    */, 1 /* ;    */,
+    1 /* <    */, 1 /* =    */, 1 /* >    */, 1 /* ?    */,
+    1 /* @    */, 1 /* A    */, 1 /* B    */, 1 /* C    */,
+    1 /* D    */, 1 /* E    */, 1 /* F    */, 1 /* G    */,
+    1 /* H    */, 1 /* I    */, 1 /* J    */, 1 /* K    */,
+    1 /* L    */, 1 /* M    */, 1 /* N    */, 1 /* O    */,
+    1 /* P    */, 1 /* Q    */, 1 /* R    */, 1 /* S    */,
+    1 /* T    */, 1 /* U    */, 1 /* V    */, 1 /* W    */,
+    1 /* X    */, 1 /* Y    */, 1 /* Z    */, 1 /* [    */,
+    1 /* \    */, 1 /* ]    */, 1 /* ^    */, 1 /* _    */,
+    1 /* `    */, 1 /* a    */, 1 /* b    */, 1 /* c    */,
+    1 /* d    */, 1 /* e    */, 1 /* f    */, 1 /* g    */,
+    1 /* h    */, 1 /* i    */, 1 /* j    */, 1 /* k    */,
+    1 /* l    */, 1 /* m    */, 1 /* n    */, 1 /* o    */,
+    1 /* p    */, 1 /* q    */, 1 /* r    */, 1 /* s    */,
+    1 /* t    */, 1 /* u    */, 1 /* v    */, 1 /* w    */,
+    1 /* x    */, 1 /* y    */, 1 /* z    */, 1 /* {    */,
+    1 /* |    */, 1 /* }    */, 1 /* ~    */, 0 /* DEL  */,
+    1 /* 0x80 */, 1 /* 0x81 */, 1 /* 0x82 */, 1 /* 0x83 */,
+    1 /* 0x84 */, 1 /* 0x85 */, 1 /* 0x86 */, 1 /* 0x87 */,
+    1 /* 0x88 */, 1 /* 0x89 */, 1 /* 0x8a */, 1 /* 0x8b */,
+    1 /* 0x8c */, 1 /* 0x8d */, 1 /* 0x8e */, 1 /* 0x8f */,
+    1 /* 0x90 */, 1 /* 0x91 */, 1 /* 0x92 */, 1 /* 0x93 */,
+    1 /* 0x94 */, 1 /* 0x95 */, 1 /* 0x96 */, 1 /* 0x97 */,
+    1 /* 0x98 */, 1 /* 0x99 */, 1 /* 0x9a */, 1 /* 0x9b */,
+    1 /* 0x9c */, 1 /* 0x9d */, 1 /* 0x9e */, 1 /* 0x9f */,
+    1 /* 0xa0 */, 1 /* 0xa1 */, 1 /* 0xa2 */, 1 /* 0xa3 */,
+    1 /* 0xa4 */, 1 /* 0xa5 */, 1 /* 0xa6 */, 1 /* 0xa7 */,
+    1 /* 0xa8 */, 1 /* 0xa9 */, 1 /* 0xaa */, 1 /* 0xab */,
+    1 /* 0xac */, 1 /* 0xad */, 1 /* 0xae */, 1 /* 0xaf */,
+    1 /* 0xb0 */, 1 /* 0xb1 */, 1 /* 0xb2 */, 1 /* 0xb3 */,
+    1 /* 0xb4 */, 1 /* 0xb5 */, 1 /* 0xb6 */, 1 /* 0xb7 */,
+    1 /* 0xb8 */, 1 /* 0xb9 */, 1 /* 0xba */, 1 /* 0xbb */,
+    1 /* 0xbc */, 1 /* 0xbd */, 1 /* 0xbe */, 1 /* 0xbf */,
+    1 /* 0xc0 */, 1 /* 0xc1 */, 1 /* 0xc2 */, 1 /* 0xc3 */,
+    1 /* 0xc4 */, 1 /* 0xc5 */, 1 /* 0xc6 */, 1 /* 0xc7 */,
+    1 /* 0xc8 */, 1 /* 0xc9 */, 1 /* 0xca */, 1 /* 0xcb */,
+    1 /* 0xcc */, 1 /* 0xcd */, 1 /* 0xce */, 1 /* 0xcf */,
+    1 /* 0xd0 */, 1 /* 0xd1 */, 1 /* 0xd2 */, 1 /* 0xd3 */,
+    1 /* 0xd4 */, 1 /* 0xd5 */, 1 /* 0xd6 */, 1 /* 0xd7 */,
+    1 /* 0xd8 */, 1 /* 0xd9 */, 1 /* 0xda */, 1 /* 0xdb */,
+    1 /* 0xdc */, 1 /* 0xdd */, 1 /* 0xde */, 1 /* 0xdf */,
+    1 /* 0xe0 */, 1 /* 0xe1 */, 1 /* 0xe2 */, 1 /* 0xe3 */,
+    1 /* 0xe4 */, 1 /* 0xe5 */, 1 /* 0xe6 */, 1 /* 0xe7 */,
+    1 /* 0xe8 */, 1 /* 0xe9 */, 1 /* 0xea */, 1 /* 0xeb */,
+    1 /* 0xec */, 1 /* 0xed */, 1 /* 0xee */, 1 /* 0xef */,
+    1 /* 0xf0 */, 1 /* 0xf1 */, 1 /* 0xf2 */, 1 /* 0xf3 */,
+    1 /* 0xf4 */, 1 /* 0xf5 */, 1 /* 0xf6 */, 1 /* 0xf7 */,
+    1 /* 0xf8 */, 1 /* 0xf9 */, 1 /* 0xfa */, 1 /* 0xfb */,
+    1 /* 0xfc */, 1 /* 0xfd */, 1 /* 0xfe */, 1 /* 0xff */
+};
+
+int nghttp2_check_path(const uint8_t *value, size_t len) {
+  const uint8_t *last;
+  for (last = value + len; value != last; ++value) {
+    if (!VALID_PATH_CHARS[*value]) {
+      return 0;
+    }
+  }
+  return 1;
+}
+
+/* Generated by genauthoritychartbl.py */
 static char VALID_AUTHORITY_CHARS[] = {
     0 /* NUL  */, 0 /* SOH  */, 0 /* STX  */, 0 /* ETX  */,
     0 /* EOT  */, 0 /* ENQ  */, 0 /* ACK  */, 0 /* BEL  */,
diff --git a/Utilities/cmnghttp2/lib/nghttp2_http.c b/Utilities/cmnghttp2/lib/nghttp2_http.c
index 62f57b6aec..83e5e6685f 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_http.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_http.c
@@ -30,6 +30,7 @@
 
 #include "nghttp2_hd.h"
 #include "nghttp2_helper.h"
+#include "nghttp2_extpri.h"
 
 static uint8_t downcase(uint8_t c) {
   return 'A' <= c && c <= 'Z' ? (uint8_t)(c - 'A' + 'a') : c;
@@ -72,25 +73,12 @@ static int64_t parse_uint(const uint8_t *s, size_t len) {
   return n;
 }
 
-static int lws(const uint8_t *s, size_t n) {
-  size_t i;
-  for (i = 0; i < n; ++i) {
-    if (s[i] != ' ' && s[i] != '\t') {
-      return 0;
-    }
-  }
-  return 1;
-}
-
 static int check_pseudo_header(nghttp2_stream *stream, const nghttp2_hd_nv *nv,
-                               int flag) {
-  if (stream->http_flags & flag) {
-    return 0;
-  }
-  if (lws(nv->value->base, nv->value->len)) {
+                               uint32_t flag) {
+  if ((stream->http_flags & flag) || nv->value->len == 0) {
     return 0;
   }
-  stream->http_flags = (uint16_t)(stream->http_flags | flag);
+  stream->http_flags = stream->http_flags | flag;
   return 1;
 }
 
@@ -114,6 +102,8 @@ static int check_path(nghttp2_stream *stream) {
 
 static int http_request_on_header(nghttp2_stream *stream, nghttp2_hd_nv *nv,
                                   int trailer, int connect_protocol) {
+  nghttp2_extpri extpri;
+
   if (nv->name->base[0] == ':') {
     if (trailer ||
         (stream->http_flags & NGHTTP2_HTTP_FLAG_PSEUDO_HEADER_DISALLOWED)) {
@@ -212,6 +202,23 @@ static int http_request_on_header(nghttp2_stream *stream, nghttp2_hd_nv *nv,
       return NGHTTP2_ERR_HTTP_HEADER;
     }
     break;
+  case NGHTTP2_TOKEN_PRIORITY:
+    if (!trailer &&
+        /* Do not parse the header field in PUSH_PROMISE. */
+        (stream->stream_id & 1) &&
+        (stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) &&
+        !(stream->http_flags & NGHTTP2_HTTP_FLAG_BAD_PRIORITY)) {
+      nghttp2_extpri_from_uint8(&extpri, stream->http_extpri);
+      if (nghttp2_http_parse_priority(&extpri, nv->value->base,
+                                      nv->value->len) == 0) {
+        stream->http_extpri = nghttp2_extpri_to_uint8(&extpri);
+        stream->http_flags |= NGHTTP2_HTTP_FLAG_PRIORITY;
+      } else {
+        stream->http_flags &= (uint32_t)~NGHTTP2_HTTP_FLAG_PRIORITY;
+        stream->http_flags |= NGHTTP2_HTTP_FLAG_BAD_PRIORITY;
+      }
+    }
+    break;
   default:
     if (nv->name->base[0] == ':') {
       return NGHTTP2_ERR_HTTP_HEADER;
@@ -329,6 +336,16 @@ static int check_scheme(const uint8_t *value, size_t len) {
   return 1;
 }
 
+static int lws(const uint8_t *s, size_t n) {
+  size_t i;
+  for (i = 0; i < n; ++i) {
+    if (s[i] != ' ' && s[i] != '\t') {
+      return 0;
+    }
+  }
+  return 1;
+}
+
 int nghttp2_http_on_header(nghttp2_session *session, nghttp2_stream *stream,
                            nghttp2_frame *frame, nghttp2_hd_nv *nv,
                            int trailer) {
@@ -360,13 +377,46 @@ int nghttp2_http_on_header(nghttp2_session *session, nghttp2_stream *stream,
     return NGHTTP2_ERR_IGN_HTTP_HEADER;
   }
 
-  if (nv->token == NGHTTP2_TOKEN__AUTHORITY ||
-      nv->token == NGHTTP2_TOKEN_HOST) {
-    rv = nghttp2_check_authority(nv->value->base, nv->value->len);
-  } else if (nv->token == NGHTTP2_TOKEN__SCHEME) {
+  switch (nv->token) {
+  case NGHTTP2_TOKEN__METHOD:
+    rv = nghttp2_check_method(nv->value->base, nv->value->len);
+    break;
+  case NGHTTP2_TOKEN__PATH:
+    rv = nghttp2_check_path(nv->value->base, nv->value->len);
+    break;
+  case NGHTTP2_TOKEN__AUTHORITY:
+  case NGHTTP2_TOKEN_HOST:
+    if (session->server || frame->hd.type == NGHTTP2_PUSH_PROMISE) {
+      rv = nghttp2_check_authority(nv->value->base, nv->value->len);
+    } else if (
+        stream->flags &
+        NGHTTP2_STREAM_FLAG_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION) {
+      rv = nghttp2_check_header_value(nv->value->base, nv->value->len);
+    } else {
+      rv = nghttp2_check_header_value_rfc9113(nv->value->base, nv->value->len);
+    }
+    break;
+  case NGHTTP2_TOKEN__SCHEME:
     rv = check_scheme(nv->value->base, nv->value->len);
-  } else {
-    rv = nghttp2_check_header_value(nv->value->base, nv->value->len);
+    break;
+  case NGHTTP2_TOKEN__PROTOCOL:
+    /* Check the value consists of just white spaces, which was done
+       in check_pseudo_header before
+       nghttp2_check_header_value_rfc9113 has been introduced. */
+    if ((stream->flags &
+         NGHTTP2_STREAM_FLAG_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION) &&
+        lws(nv->value->base, nv->value->len)) {
+      rv = 0;
+      break;
+    }
+    /* fall through */
+  default:
+    if (stream->flags &
+        NGHTTP2_STREAM_FLAG_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION) {
+      rv = nghttp2_check_header_value(nv->value->base, nv->value->len);
+    } else {
+      rv = nghttp2_check_header_value_rfc9113(nv->value->base, nv->value->len);
+    }
   }
 
   if (rv == 0) {
@@ -434,16 +484,15 @@ int nghttp2_http_on_response_headers(nghttp2_stream *stream) {
 
   if (stream->status_code / 100 == 1) {
     /* non-final response */
-    stream->http_flags =
-        (uint16_t)((stream->http_flags & NGHTTP2_HTTP_FLAG_METH_ALL) |
-                   NGHTTP2_HTTP_FLAG_EXPECT_FINAL_RESPONSE);
+    stream->http_flags = (stream->http_flags & NGHTTP2_HTTP_FLAG_METH_ALL) |
+                         NGHTTP2_HTTP_FLAG_EXPECT_FINAL_RESPONSE;
     stream->content_length = -1;
     stream->status_code = -1;
     return 0;
   }
 
   stream->http_flags =
-      (uint16_t)(stream->http_flags & ~NGHTTP2_HTTP_FLAG_EXPECT_FINAL_RESPONSE);
+      stream->http_flags & (uint32_t)~NGHTTP2_HTTP_FLAG_EXPECT_FINAL_RESPONSE;
 
   if (!expect_response_body(stream)) {
     stream->content_length = 0;
@@ -528,3 +577,715 @@ void nghttp2_http_record_request_method(nghttp2_stream *stream,
     return;
   }
 }
+
+/* Generated by genchartbl.py */
+static const int SF_KEY_CHARS[] = {
+    0 /* NUL  */, 0 /* SOH  */, 0 /* STX  */, 0 /* ETX  */, 0 /* EOT  */,
+    0 /* ENQ  */, 0 /* ACK  */, 0 /* BEL  */, 0 /* BS   */, 0 /* HT   */,
+    0 /* LF   */, 0 /* VT   */, 0 /* FF   */, 0 /* CR   */, 0 /* SO   */,
+    0 /* SI   */, 0 /* DLE  */, 0 /* DC1  */, 0 /* DC2  */, 0 /* DC3  */,
+    0 /* DC4  */, 0 /* NAK  */, 0 /* SYN  */, 0 /* ETB  */, 0 /* CAN  */,
+    0 /* EM   */, 0 /* SUB  */, 0 /* ESC  */, 0 /* FS   */, 0 /* GS   */,
+    0 /* RS   */, 0 /* US   */, 0 /* SPC  */, 0 /* !    */, 0 /* "    */,
+    0 /* #    */, 0 /* $    */, 0 /* %    */, 0 /* &    */, 0 /* '    */,
+    0 /* (    */, 0 /* )    */, 1 /* *    */, 0 /* +    */, 0 /* ,    */,
+    1 /* -    */, 1 /* .    */, 0 /* /    */, 1 /* 0    */, 1 /* 1    */,
+    1 /* 2    */, 1 /* 3    */, 1 /* 4    */, 1 /* 5    */, 1 /* 6    */,
+    1 /* 7    */, 1 /* 8    */, 1 /* 9    */, 0 /* :    */, 0 /* ;    */,
+    0 /* <    */, 0 /* =    */, 0 /* >    */, 0 /* ?    */, 0 /* @    */,
+    0 /* A    */, 0 /* B    */, 0 /* C    */, 0 /* D    */, 0 /* E    */,
+    0 /* F    */, 0 /* G    */, 0 /* H    */, 0 /* I    */, 0 /* J    */,
+    0 /* K    */, 0 /* L    */, 0 /* M    */, 0 /* N    */, 0 /* O    */,
+    0 /* P    */, 0 /* Q    */, 0 /* R    */, 0 /* S    */, 0 /* T    */,
+    0 /* U    */, 0 /* V    */, 0 /* W    */, 0 /* X    */, 0 /* Y    */,
+    0 /* Z    */, 0 /* [    */, 0 /* \    */, 0 /* ]    */, 0 /* ^    */,
+    1 /* _    */, 0 /* `    */, 1 /* a    */, 1 /* b    */, 1 /* c    */,
+    1 /* d    */, 1 /* e    */, 1 /* f    */, 1 /* g    */, 1 /* h    */,
+    1 /* i    */, 1 /* j    */, 1 /* k    */, 1 /* l    */, 1 /* m    */,
+    1 /* n    */, 1 /* o    */, 1 /* p    */, 1 /* q    */, 1 /* r    */,
+    1 /* s    */, 1 /* t    */, 1 /* u    */, 1 /* v    */, 1 /* w    */,
+    1 /* x    */, 1 /* y    */, 1 /* z    */, 0 /* {    */, 0 /* |    */,
+    0 /* }    */, 0 /* ~    */, 0 /* DEL  */, 0 /* 0x80 */, 0 /* 0x81 */,
+    0 /* 0x82 */, 0 /* 0x83 */, 0 /* 0x84 */, 0 /* 0x85 */, 0 /* 0x86 */,
+    0 /* 0x87 */, 0 /* 0x88 */, 0 /* 0x89 */, 0 /* 0x8a */, 0 /* 0x8b */,
+    0 /* 0x8c */, 0 /* 0x8d */, 0 /* 0x8e */, 0 /* 0x8f */, 0 /* 0x90 */,
+    0 /* 0x91 */, 0 /* 0x92 */, 0 /* 0x93 */, 0 /* 0x94 */, 0 /* 0x95 */,
+    0 /* 0x96 */, 0 /* 0x97 */, 0 /* 0x98 */, 0 /* 0x99 */, 0 /* 0x9a */,
+    0 /* 0x9b */, 0 /* 0x9c */, 0 /* 0x9d */, 0 /* 0x9e */, 0 /* 0x9f */,
+    0 /* 0xa0 */, 0 /* 0xa1 */, 0 /* 0xa2 */, 0 /* 0xa3 */, 0 /* 0xa4 */,
+    0 /* 0xa5 */, 0 /* 0xa6 */, 0 /* 0xa7 */, 0 /* 0xa8 */, 0 /* 0xa9 */,
+    0 /* 0xaa */, 0 /* 0xab */, 0 /* 0xac */, 0 /* 0xad */, 0 /* 0xae */,
+    0 /* 0xaf */, 0 /* 0xb0 */, 0 /* 0xb1 */, 0 /* 0xb2 */, 0 /* 0xb3 */,
+    0 /* 0xb4 */, 0 /* 0xb5 */, 0 /* 0xb6 */, 0 /* 0xb7 */, 0 /* 0xb8 */,
+    0 /* 0xb9 */, 0 /* 0xba */, 0 /* 0xbb */, 0 /* 0xbc */, 0 /* 0xbd */,
+    0 /* 0xbe */, 0 /* 0xbf */, 0 /* 0xc0 */, 0 /* 0xc1 */, 0 /* 0xc2 */,
+    0 /* 0xc3 */, 0 /* 0xc4 */, 0 /* 0xc5 */, 0 /* 0xc6 */, 0 /* 0xc7 */,
+    0 /* 0xc8 */, 0 /* 0xc9 */, 0 /* 0xca */, 0 /* 0xcb */, 0 /* 0xcc */,
+    0 /* 0xcd */, 0 /* 0xce */, 0 /* 0xcf */, 0 /* 0xd0 */, 0 /* 0xd1 */,
+    0 /* 0xd2 */, 0 /* 0xd3 */, 0 /* 0xd4 */, 0 /* 0xd5 */, 0 /* 0xd6 */,
+    0 /* 0xd7 */, 0 /* 0xd8 */, 0 /* 0xd9 */, 0 /* 0xda */, 0 /* 0xdb */,
+    0 /* 0xdc */, 0 /* 0xdd */, 0 /* 0xde */, 0 /* 0xdf */, 0 /* 0xe0 */,
+    0 /* 0xe1 */, 0 /* 0xe2 */, 0 /* 0xe3 */, 0 /* 0xe4 */, 0 /* 0xe5 */,
+    0 /* 0xe6 */, 0 /* 0xe7 */, 0 /* 0xe8 */, 0 /* 0xe9 */, 0 /* 0xea */,
+    0 /* 0xeb */, 0 /* 0xec */, 0 /* 0xed */, 0 /* 0xee */, 0 /* 0xef */,
+    0 /* 0xf0 */, 0 /* 0xf1 */, 0 /* 0xf2 */, 0 /* 0xf3 */, 0 /* 0xf4 */,
+    0 /* 0xf5 */, 0 /* 0xf6 */, 0 /* 0xf7 */, 0 /* 0xf8 */, 0 /* 0xf9 */,
+    0 /* 0xfa */, 0 /* 0xfb */, 0 /* 0xfc */, 0 /* 0xfd */, 0 /* 0xfe */,
+    0 /* 0xff */,
+};
+
+static ssize_t sf_parse_key(const uint8_t *begin, const uint8_t *end) {
+  const uint8_t *p = begin;
+
+  if ((*p < 'a' || 'z' < *p) && *p != '*') {
+    return -1;
+  }
+
+  for (; p != end && SF_KEY_CHARS[*p]; ++p)
+    ;
+
+  return p - begin;
+}
+
+static ssize_t sf_parse_integer_or_decimal(nghttp2_sf_value *dest,
+                                           const uint8_t *begin,
+                                           const uint8_t *end) {
+  const uint8_t *p = begin;
+  int sign = 1;
+  int64_t value = 0;
+  int type = NGHTTP2_SF_VALUE_TYPE_INTEGER;
+  size_t len = 0;
+  size_t fpos = 0;
+  size_t i;
+
+  if (*p == '-') {
+    if (++p == end) {
+      return -1;
+    }
+
+    sign = -1;
+  }
+
+  if (*p < '0' || '9' < *p) {
+    return -1;
+  }
+
+  for (; p != end; ++p) {
+    switch (*p) {
+    case '0':
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9':
+      value *= 10;
+      value += *p - '0';
+
+      if (++len > 15) {
+        return -1;
+      }
+
+      break;
+    case '.':
+      if (type != NGHTTP2_SF_VALUE_TYPE_INTEGER) {
+        goto fin;
+      }
+
+      if (len > 12) {
+        return -1;
+      }
+      fpos = len;
+      type = NGHTTP2_SF_VALUE_TYPE_DECIMAL;
+
+      break;
+    default:
+      goto fin;
+    };
+  }
+
+fin:
+  switch (type) {
+  case NGHTTP2_SF_VALUE_TYPE_INTEGER:
+    if (dest) {
+      dest->type = (uint8_t)type;
+      dest->i = value * sign;
+    }
+
+    return p - begin;
+  case NGHTTP2_SF_VALUE_TYPE_DECIMAL:
+    if (fpos == len || len - fpos > 3) {
+      return -1;
+    }
+
+    if (dest) {
+      dest->type = (uint8_t)type;
+      dest->d = (double)value;
+      for (i = len - fpos; i > 0; --i) {
+        dest->d /= (double)10;
+      }
+      dest->d *= sign;
+    }
+
+    return p - begin;
+  default:
+    assert(0);
+    abort();
+  }
+}
+
+/* Generated by genchartbl.py */
+static const int SF_DQUOTE_CHARS[] = {
+    0 /* NUL  */, 0 /* SOH  */, 0 /* STX  */, 0 /* ETX  */, 0 /* EOT  */,
+    0 /* ENQ  */, 0 /* ACK  */, 0 /* BEL  */, 0 /* BS   */, 0 /* HT   */,
+    0 /* LF   */, 0 /* VT   */, 0 /* FF   */, 0 /* CR   */, 0 /* SO   */,
+    0 /* SI   */, 0 /* DLE  */, 0 /* DC1  */, 0 /* DC2  */, 0 /* DC3  */,
+    0 /* DC4  */, 0 /* NAK  */, 0 /* SYN  */, 0 /* ETB  */, 0 /* CAN  */,
+    0 /* EM   */, 0 /* SUB  */, 0 /* ESC  */, 0 /* FS   */, 0 /* GS   */,
+    0 /* RS   */, 0 /* US   */, 1 /* SPC  */, 1 /* !    */, 0 /* "    */,
+    1 /* #    */, 1 /* $    */, 1 /* %    */, 1 /* &    */, 1 /* '    */,
+    1 /* (    */, 1 /* )    */, 1 /* *    */, 1 /* +    */, 1 /* ,    */,
+    1 /* -    */, 1 /* .    */, 1 /* /    */, 1 /* 0    */, 1 /* 1    */,
+    1 /* 2    */, 1 /* 3    */, 1 /* 4    */, 1 /* 5    */, 1 /* 6    */,
+    1 /* 7    */, 1 /* 8    */, 1 /* 9    */, 1 /* :    */, 1 /* ;    */,
+    1 /* <    */, 1 /* =    */, 1 /* >    */, 1 /* ?    */, 1 /* @    */,
+    1 /* A    */, 1 /* B    */, 1 /* C    */, 1 /* D    */, 1 /* E    */,
+    1 /* F    */, 1 /* G    */, 1 /* H    */, 1 /* I    */, 1 /* J    */,
+    1 /* K    */, 1 /* L    */, 1 /* M    */, 1 /* N    */, 1 /* O    */,
+    1 /* P    */, 1 /* Q    */, 1 /* R    */, 1 /* S    */, 1 /* T    */,
+    1 /* U    */, 1 /* V    */, 1 /* W    */, 1 /* X    */, 1 /* Y    */,
+    1 /* Z    */, 1 /* [    */, 0 /* \    */, 1 /* ]    */, 1 /* ^    */,
+    1 /* _    */, 1 /* `    */, 1 /* a    */, 1 /* b    */, 1 /* c    */,
+    1 /* d    */, 1 /* e    */, 1 /* f    */, 1 /* g    */, 1 /* h    */,
+    1 /* i    */, 1 /* j    */, 1 /* k    */, 1 /* l    */, 1 /* m    */,
+    1 /* n    */, 1 /* o    */, 1 /* p    */, 1 /* q    */, 1 /* r    */,
+    1 /* s    */, 1 /* t    */, 1 /* u    */, 1 /* v    */, 1 /* w    */,
+    1 /* x    */, 1 /* y    */, 1 /* z    */, 1 /* {    */, 1 /* |    */,
+    1 /* }    */, 1 /* ~    */, 0 /* DEL  */, 0 /* 0x80 */, 0 /* 0x81 */,
+    0 /* 0x82 */, 0 /* 0x83 */, 0 /* 0x84 */, 0 /* 0x85 */, 0 /* 0x86 */,
+    0 /* 0x87 */, 0 /* 0x88 */, 0 /* 0x89 */, 0 /* 0x8a */, 0 /* 0x8b */,
+    0 /* 0x8c */, 0 /* 0x8d */, 0 /* 0x8e */, 0 /* 0x8f */, 0 /* 0x90 */,
+    0 /* 0x91 */, 0 /* 0x92 */, 0 /* 0x93 */, 0 /* 0x94 */, 0 /* 0x95 */,
+    0 /* 0x96 */, 0 /* 0x97 */, 0 /* 0x98 */, 0 /* 0x99 */, 0 /* 0x9a */,
+    0 /* 0x9b */, 0 /* 0x9c */, 0 /* 0x9d */, 0 /* 0x9e */, 0 /* 0x9f */,
+    0 /* 0xa0 */, 0 /* 0xa1 */, 0 /* 0xa2 */, 0 /* 0xa3 */, 0 /* 0xa4 */,
+    0 /* 0xa5 */, 0 /* 0xa6 */, 0 /* 0xa7 */, 0 /* 0xa8 */, 0 /* 0xa9 */,
+    0 /* 0xaa */, 0 /* 0xab */, 0 /* 0xac */, 0 /* 0xad */, 0 /* 0xae */,
+    0 /* 0xaf */, 0 /* 0xb0 */, 0 /* 0xb1 */, 0 /* 0xb2 */, 0 /* 0xb3 */,
+    0 /* 0xb4 */, 0 /* 0xb5 */, 0 /* 0xb6 */, 0 /* 0xb7 */, 0 /* 0xb8 */,
+    0 /* 0xb9 */, 0 /* 0xba */, 0 /* 0xbb */, 0 /* 0xbc */, 0 /* 0xbd */,
+    0 /* 0xbe */, 0 /* 0xbf */, 0 /* 0xc0 */, 0 /* 0xc1 */, 0 /* 0xc2 */,
+    0 /* 0xc3 */, 0 /* 0xc4 */, 0 /* 0xc5 */, 0 /* 0xc6 */, 0 /* 0xc7 */,
+    0 /* 0xc8 */, 0 /* 0xc9 */, 0 /* 0xca */, 0 /* 0xcb */, 0 /* 0xcc */,
+    0 /* 0xcd */, 0 /* 0xce */, 0 /* 0xcf */, 0 /* 0xd0 */, 0 /* 0xd1 */,
+    0 /* 0xd2 */, 0 /* 0xd3 */, 0 /* 0xd4 */, 0 /* 0xd5 */, 0 /* 0xd6 */,
+    0 /* 0xd7 */, 0 /* 0xd8 */, 0 /* 0xd9 */, 0 /* 0xda */, 0 /* 0xdb */,
+    0 /* 0xdc */, 0 /* 0xdd */, 0 /* 0xde */, 0 /* 0xdf */, 0 /* 0xe0 */,
+    0 /* 0xe1 */, 0 /* 0xe2 */, 0 /* 0xe3 */, 0 /* 0xe4 */, 0 /* 0xe5 */,
+    0 /* 0xe6 */, 0 /* 0xe7 */, 0 /* 0xe8 */, 0 /* 0xe9 */, 0 /* 0xea */,
+    0 /* 0xeb */, 0 /* 0xec */, 0 /* 0xed */, 0 /* 0xee */, 0 /* 0xef */,
+    0 /* 0xf0 */, 0 /* 0xf1 */, 0 /* 0xf2 */, 0 /* 0xf3 */, 0 /* 0xf4 */,
+    0 /* 0xf5 */, 0 /* 0xf6 */, 0 /* 0xf7 */, 0 /* 0xf8 */, 0 /* 0xf9 */,
+    0 /* 0xfa */, 0 /* 0xfb */, 0 /* 0xfc */, 0 /* 0xfd */, 0 /* 0xfe */,
+    0 /* 0xff */,
+};
+
+static ssize_t sf_parse_string(nghttp2_sf_value *dest, const uint8_t *begin,
+                               const uint8_t *end) {
+  const uint8_t *p = begin;
+
+  if (*p++ != '"') {
+    return -1;
+  }
+
+  for (; p != end; ++p) {
+    switch (*p) {
+    case '\\':
+      if (++p == end) {
+        return -1;
+      }
+
+      switch (*p) {
+      case '"':
+      case '\\':
+        break;
+      default:
+        return -1;
+      }
+
+      break;
+    case '"':
+      if (dest) {
+        dest->type = NGHTTP2_SF_VALUE_TYPE_STRING;
+        dest->s.base = begin + 1;
+        dest->s.len = (size_t)(p - dest->s.base);
+      }
+
+      ++p;
+
+      return p - begin;
+    default:
+      if (!SF_DQUOTE_CHARS[*p]) {
+        return -1;
+      }
+    }
+  }
+
+  return -1;
+}
+
+/* Generated by genchartbl.py */
+static const int SF_TOKEN_CHARS[] = {
+    0 /* NUL  */, 0 /* SOH  */, 0 /* STX  */, 0 /* ETX  */, 0 /* EOT  */,
+    0 /* ENQ  */, 0 /* ACK  */, 0 /* BEL  */, 0 /* BS   */, 0 /* HT   */,
+    0 /* LF   */, 0 /* VT   */, 0 /* FF   */, 0 /* CR   */, 0 /* SO   */,
+    0 /* SI   */, 0 /* DLE  */, 0 /* DC1  */, 0 /* DC2  */, 0 /* DC3  */,
+    0 /* DC4  */, 0 /* NAK  */, 0 /* SYN  */, 0 /* ETB  */, 0 /* CAN  */,
+    0 /* EM   */, 0 /* SUB  */, 0 /* ESC  */, 0 /* FS   */, 0 /* GS   */,
+    0 /* RS   */, 0 /* US   */, 0 /* SPC  */, 1 /* !    */, 0 /* "    */,
+    1 /* #    */, 1 /* $    */, 1 /* %    */, 1 /* &    */, 1 /* '    */,
+    0 /* (    */, 0 /* )    */, 1 /* *    */, 1 /* +    */, 0 /* ,    */,
+    1 /* -    */, 1 /* .    */, 1 /* /    */, 1 /* 0    */, 1 /* 1    */,
+    1 /* 2    */, 1 /* 3    */, 1 /* 4    */, 1 /* 5    */, 1 /* 6    */,
+    1 /* 7    */, 1 /* 8    */, 1 /* 9    */, 1 /* :    */, 0 /* ;    */,
+    0 /* <    */, 0 /* =    */, 0 /* >    */, 0 /* ?    */, 0 /* @    */,
+    1 /* A    */, 1 /* B    */, 1 /* C    */, 1 /* D    */, 1 /* E    */,
+    1 /* F    */, 1 /* G    */, 1 /* H    */, 1 /* I    */, 1 /* J    */,
+    1 /* K    */, 1 /* L    */, 1 /* M    */, 1 /* N    */, 1 /* O    */,
+    1 /* P    */, 1 /* Q    */, 1 /* R    */, 1 /* S    */, 1 /* T    */,
+    1 /* U    */, 1 /* V    */, 1 /* W    */, 1 /* X    */, 1 /* Y    */,
+    1 /* Z    */, 0 /* [    */, 0 /* \    */, 0 /* ]    */, 1 /* ^    */,
+    1 /* _    */, 1 /* `    */, 1 /* a    */, 1 /* b    */, 1 /* c    */,
+    1 /* d    */, 1 /* e    */, 1 /* f    */, 1 /* g    */, 1 /* h    */,
+    1 /* i    */, 1 /* j    */, 1 /* k    */, 1 /* l    */, 1 /* m    */,
+    1 /* n    */, 1 /* o    */, 1 /* p    */, 1 /* q    */, 1 /* r    */,
+    1 /* s    */, 1 /* t    */, 1 /* u    */, 1 /* v    */, 1 /* w    */,
+    1 /* x    */, 1 /* y    */, 1 /* z    */, 0 /* {    */, 1 /* |    */,
+    0 /* }    */, 1 /* ~    */, 0 /* DEL  */, 0 /* 0x80 */, 0 /* 0x81 */,
+    0 /* 0x82 */, 0 /* 0x83 */, 0 /* 0x84 */, 0 /* 0x85 */, 0 /* 0x86 */,
+    0 /* 0x87 */, 0 /* 0x88 */, 0 /* 0x89 */, 0 /* 0x8a */, 0 /* 0x8b */,
+    0 /* 0x8c */, 0 /* 0x8d */, 0 /* 0x8e */, 0 /* 0x8f */, 0 /* 0x90 */,
+    0 /* 0x91 */, 0 /* 0x92 */, 0 /* 0x93 */, 0 /* 0x94 */, 0 /* 0x95 */,
+    0 /* 0x96 */, 0 /* 0x97 */, 0 /* 0x98 */, 0 /* 0x99 */, 0 /* 0x9a */,
+    0 /* 0x9b */, 0 /* 0x9c */, 0 /* 0x9d */, 0 /* 0x9e */, 0 /* 0x9f */,
+    0 /* 0xa0 */, 0 /* 0xa1 */, 0 /* 0xa2 */, 0 /* 0xa3 */, 0 /* 0xa4 */,
+    0 /* 0xa5 */, 0 /* 0xa6 */, 0 /* 0xa7 */, 0 /* 0xa8 */, 0 /* 0xa9 */,
+    0 /* 0xaa */, 0 /* 0xab */, 0 /* 0xac */, 0 /* 0xad */, 0 /* 0xae */,
+    0 /* 0xaf */, 0 /* 0xb0 */, 0 /* 0xb1 */, 0 /* 0xb2 */, 0 /* 0xb3 */,
+    0 /* 0xb4 */, 0 /* 0xb5 */, 0 /* 0xb6 */, 0 /* 0xb7 */, 0 /* 0xb8 */,
+    0 /* 0xb9 */, 0 /* 0xba */, 0 /* 0xbb */, 0 /* 0xbc */, 0 /* 0xbd */,
+    0 /* 0xbe */, 0 /* 0xbf */, 0 /* 0xc0 */, 0 /* 0xc1 */, 0 /* 0xc2 */,
+    0 /* 0xc3 */, 0 /* 0xc4 */, 0 /* 0xc5 */, 0 /* 0xc6 */, 0 /* 0xc7 */,
+    0 /* 0xc8 */, 0 /* 0xc9 */, 0 /* 0xca */, 0 /* 0xcb */, 0 /* 0xcc */,
+    0 /* 0xcd */, 0 /* 0xce */, 0 /* 0xcf */, 0 /* 0xd0 */, 0 /* 0xd1 */,
+    0 /* 0xd2 */, 0 /* 0xd3 */, 0 /* 0xd4 */, 0 /* 0xd5 */, 0 /* 0xd6 */,
+    0 /* 0xd7 */, 0 /* 0xd8 */, 0 /* 0xd9 */, 0 /* 0xda */, 0 /* 0xdb */,
+    0 /* 0xdc */, 0 /* 0xdd */, 0 /* 0xde */, 0 /* 0xdf */, 0 /* 0xe0 */,
+    0 /* 0xe1 */, 0 /* 0xe2 */, 0 /* 0xe3 */, 0 /* 0xe4 */, 0 /* 0xe5 */,
+    0 /* 0xe6 */, 0 /* 0xe7 */, 0 /* 0xe8 */, 0 /* 0xe9 */, 0 /* 0xea */,
+    0 /* 0xeb */, 0 /* 0xec */, 0 /* 0xed */, 0 /* 0xee */, 0 /* 0xef */,
+    0 /* 0xf0 */, 0 /* 0xf1 */, 0 /* 0xf2 */, 0 /* 0xf3 */, 0 /* 0xf4 */,
+    0 /* 0xf5 */, 0 /* 0xf6 */, 0 /* 0xf7 */, 0 /* 0xf8 */, 0 /* 0xf9 */,
+    0 /* 0xfa */, 0 /* 0xfb */, 0 /* 0xfc */, 0 /* 0xfd */, 0 /* 0xfe */,
+    0 /* 0xff */,
+};
+
+static ssize_t sf_parse_token(nghttp2_sf_value *dest, const uint8_t *begin,
+                              const uint8_t *end) {
+  const uint8_t *p = begin;
+
+  if ((*p < 'A' || 'Z' < *p) && (*p < 'a' || 'z' < *p) && *p != '*') {
+    return -1;
+  }
+
+  for (; p != end && SF_TOKEN_CHARS[*p]; ++p)
+    ;
+
+  if (dest) {
+    dest->type = NGHTTP2_SF_VALUE_TYPE_TOKEN;
+    dest->s.base = begin;
+    dest->s.len = (size_t)(p - begin);
+  }
+
+  return p - begin;
+}
+
+/* Generated by genchartbl.py */
+static const int SF_BYTESEQ_CHARS[] = {
+    0 /* NUL  */, 0 /* SOH  */, 0 /* STX  */, 0 /* ETX  */, 0 /* EOT  */,
+    0 /* ENQ  */, 0 /* ACK  */, 0 /* BEL  */, 0 /* BS   */, 0 /* HT   */,
+    0 /* LF   */, 0 /* VT   */, 0 /* FF   */, 0 /* CR   */, 0 /* SO   */,
+    0 /* SI   */, 0 /* DLE  */, 0 /* DC1  */, 0 /* DC2  */, 0 /* DC3  */,
+    0 /* DC4  */, 0 /* NAK  */, 0 /* SYN  */, 0 /* ETB  */, 0 /* CAN  */,
+    0 /* EM   */, 0 /* SUB  */, 0 /* ESC  */, 0 /* FS   */, 0 /* GS   */,
+    0 /* RS   */, 0 /* US   */, 0 /* SPC  */, 0 /* !    */, 0 /* "    */,
+    0 /* #    */, 0 /* $    */, 0 /* %    */, 0 /* &    */, 0 /* '    */,
+    0 /* (    */, 0 /* )    */, 0 /* *    */, 1 /* +    */, 0 /* ,    */,
+    0 /* -    */, 0 /* .    */, 1 /* /    */, 1 /* 0    */, 1 /* 1    */,
+    1 /* 2    */, 1 /* 3    */, 1 /* 4    */, 1 /* 5    */, 1 /* 6    */,
+    1 /* 7    */, 1 /* 8    */, 1 /* 9    */, 0 /* :    */, 0 /* ;    */,
+    0 /* <    */, 1 /* =    */, 0 /* >    */, 0 /* ?    */, 0 /* @    */,
+    1 /* A    */, 1 /* B    */, 1 /* C    */, 1 /* D    */, 1 /* E    */,
+    1 /* F    */, 1 /* G    */, 1 /* H    */, 1 /* I    */, 1 /* J    */,
+    1 /* K    */, 1 /* L    */, 1 /* M    */, 1 /* N    */, 1 /* O    */,
+    1 /* P    */, 1 /* Q    */, 1 /* R    */, 1 /* S    */, 1 /* T    */,
+    1 /* U    */, 1 /* V    */, 1 /* W    */, 1 /* X    */, 1 /* Y    */,
+    1 /* Z    */, 0 /* [    */, 0 /* \    */, 0 /* ]    */, 0 /* ^    */,
+    0 /* _    */, 0 /* `    */, 1 /* a    */, 1 /* b    */, 1 /* c    */,
+    1 /* d    */, 1 /* e    */, 1 /* f    */, 1 /* g    */, 1 /* h    */,
+    1 /* i    */, 1 /* j    */, 1 /* k    */, 1 /* l    */, 1 /* m    */,
+    1 /* n    */, 1 /* o    */, 1 /* p    */, 1 /* q    */, 1 /* r    */,
+    1 /* s    */, 1 /* t    */, 1 /* u    */, 1 /* v    */, 1 /* w    */,
+    1 /* x    */, 1 /* y    */, 1 /* z    */, 0 /* {    */, 0 /* |    */,
+    0 /* }    */, 0 /* ~    */, 0 /* DEL  */, 0 /* 0x80 */, 0 /* 0x81 */,
+    0 /* 0x82 */, 0 /* 0x83 */, 0 /* 0x84 */, 0 /* 0x85 */, 0 /* 0x86 */,
+    0 /* 0x87 */, 0 /* 0x88 */, 0 /* 0x89 */, 0 /* 0x8a */, 0 /* 0x8b */,
+    0 /* 0x8c */, 0 /* 0x8d */, 0 /* 0x8e */, 0 /* 0x8f */, 0 /* 0x90 */,
+    0 /* 0x91 */, 0 /* 0x92 */, 0 /* 0x93 */, 0 /* 0x94 */, 0 /* 0x95 */,
+    0 /* 0x96 */, 0 /* 0x97 */, 0 /* 0x98 */, 0 /* 0x99 */, 0 /* 0x9a */,
+    0 /* 0x9b */, 0 /* 0x9c */, 0 /* 0x9d */, 0 /* 0x9e */, 0 /* 0x9f */,
+    0 /* 0xa0 */, 0 /* 0xa1 */, 0 /* 0xa2 */, 0 /* 0xa3 */, 0 /* 0xa4 */,
+    0 /* 0xa5 */, 0 /* 0xa6 */, 0 /* 0xa7 */, 0 /* 0xa8 */, 0 /* 0xa9 */,
+    0 /* 0xaa */, 0 /* 0xab */, 0 /* 0xac */, 0 /* 0xad */, 0 /* 0xae */,
+    0 /* 0xaf */, 0 /* 0xb0 */, 0 /* 0xb1 */, 0 /* 0xb2 */, 0 /* 0xb3 */,
+    0 /* 0xb4 */, 0 /* 0xb5 */, 0 /* 0xb6 */, 0 /* 0xb7 */, 0 /* 0xb8 */,
+    0 /* 0xb9 */, 0 /* 0xba */, 0 /* 0xbb */, 0 /* 0xbc */, 0 /* 0xbd */,
+    0 /* 0xbe */, 0 /* 0xbf */, 0 /* 0xc0 */, 0 /* 0xc1 */, 0 /* 0xc2 */,
+    0 /* 0xc3 */, 0 /* 0xc4 */, 0 /* 0xc5 */, 0 /* 0xc6 */, 0 /* 0xc7 */,
+    0 /* 0xc8 */, 0 /* 0xc9 */, 0 /* 0xca */, 0 /* 0xcb */, 0 /* 0xcc */,
+    0 /* 0xcd */, 0 /* 0xce */, 0 /* 0xcf */, 0 /* 0xd0 */, 0 /* 0xd1 */,
+    0 /* 0xd2 */, 0 /* 0xd3 */, 0 /* 0xd4 */, 0 /* 0xd5 */, 0 /* 0xd6 */,
+    0 /* 0xd7 */, 0 /* 0xd8 */, 0 /* 0xd9 */, 0 /* 0xda */, 0 /* 0xdb */,
+    0 /* 0xdc */, 0 /* 0xdd */, 0 /* 0xde */, 0 /* 0xdf */, 0 /* 0xe0 */,
+    0 /* 0xe1 */, 0 /* 0xe2 */, 0 /* 0xe3 */, 0 /* 0xe4 */, 0 /* 0xe5 */,
+    0 /* 0xe6 */, 0 /* 0xe7 */, 0 /* 0xe8 */, 0 /* 0xe9 */, 0 /* 0xea */,
+    0 /* 0xeb */, 0 /* 0xec */, 0 /* 0xed */, 0 /* 0xee */, 0 /* 0xef */,
+    0 /* 0xf0 */, 0 /* 0xf1 */, 0 /* 0xf2 */, 0 /* 0xf3 */, 0 /* 0xf4 */,
+    0 /* 0xf5 */, 0 /* 0xf6 */, 0 /* 0xf7 */, 0 /* 0xf8 */, 0 /* 0xf9 */,
+    0 /* 0xfa */, 0 /* 0xfb */, 0 /* 0xfc */, 0 /* 0xfd */, 0 /* 0xfe */,
+    0 /* 0xff */,
+};
+
+static ssize_t sf_parse_byteseq(nghttp2_sf_value *dest, const uint8_t *begin,
+                                const uint8_t *end) {
+  const uint8_t *p = begin;
+
+  if (*p++ != ':') {
+    return -1;
+  }
+
+  for (; p != end; ++p) {
+    switch (*p) {
+    case ':':
+      if (dest) {
+        dest->type = NGHTTP2_SF_VALUE_TYPE_BYTESEQ;
+        dest->s.base = begin + 1;
+        dest->s.len = (size_t)(p - dest->s.base);
+      }
+
+      ++p;
+
+      return p - begin;
+    default:
+      if (!SF_BYTESEQ_CHARS[*p]) {
+        return -1;
+      }
+    }
+  }
+
+  return -1;
+}
+
+static ssize_t sf_parse_boolean(nghttp2_sf_value *dest, const uint8_t *begin,
+                                const uint8_t *end) {
+  const uint8_t *p = begin;
+  int b;
+
+  if (*p++ != '?') {
+    return -1;
+  }
+
+  if (p == end) {
+    return -1;
+  }
+
+  switch (*p++) {
+  case '0':
+    b = 0;
+    break;
+  case '1':
+    b = 1;
+    break;
+  default:
+    return -1;
+  }
+
+  if (dest) {
+    dest->type = NGHTTP2_SF_VALUE_TYPE_BOOLEAN;
+    dest->b = b;
+  }
+
+  return p - begin;
+}
+
+static ssize_t sf_parse_bare_item(nghttp2_sf_value *dest, const uint8_t *begin,
+                                  const uint8_t *end) {
+  switch (*begin) {
+  case '-':
+  case '0':
+  case '1':
+  case '2':
+  case '3':
+  case '4':
+  case '5':
+  case '6':
+  case '7':
+  case '8':
+  case '9':
+    return sf_parse_integer_or_decimal(dest, begin, end);
+  case '"':
+    return sf_parse_string(dest, begin, end);
+  case '*':
+    return sf_parse_token(dest, begin, end);
+  case ':':
+    return sf_parse_byteseq(dest, begin, end);
+  case '?':
+    return sf_parse_boolean(dest, begin, end);
+  default:
+    if (('A' <= *begin && *begin <= 'Z') || ('a' <= *begin && *begin <= 'z')) {
+      return sf_parse_token(dest, begin, end);
+    }
+    return -1;
+  }
+}
+
+#define sf_discard_sp_end_err(BEGIN, END, ERR)                                 \
+  for (;; ++(BEGIN)) {                                                         \
+    if ((BEGIN) == (END)) {                                                    \
+      return (ERR);                                                            \
+    }                                                                          \
+    if (*(BEGIN) != ' ') {                                                     \
+      break;                                                                   \
+    }                                                                          \
+  }
+
+static ssize_t sf_parse_params(const uint8_t *begin, const uint8_t *end) {
+  const uint8_t *p = begin;
+  ssize_t slen;
+
+  for (; p != end && *p == ';';) {
+    ++p;
+
+    sf_discard_sp_end_err(p, end, -1);
+
+    slen = sf_parse_key(p, end);
+    if (slen < 0) {
+      return -1;
+    }
+
+    p += slen;
+
+    if (p == end || *p != '=') {
+      /* Boolean true */
+    } else if (++p == end) {
+      return -1;
+    } else {
+      slen = sf_parse_bare_item(NULL, p, end);
+      if (slen < 0) {
+        return -1;
+      }
+
+      p += slen;
+    }
+  }
+
+  return p - begin;
+}
+
+static ssize_t sf_parse_item(nghttp2_sf_value *dest, const uint8_t *begin,
+                             const uint8_t *end) {
+  const uint8_t *p = begin;
+  ssize_t slen;
+
+  slen = sf_parse_bare_item(dest, p, end);
+  if (slen < 0) {
+    return -1;
+  }
+
+  p += slen;
+
+  slen = sf_parse_params(p, end);
+  if (slen < 0) {
+    return -1;
+  }
+
+  p += slen;
+
+  return p - begin;
+}
+
+ssize_t nghttp2_sf_parse_item(nghttp2_sf_value *dest, const uint8_t *begin,
+                              const uint8_t *end) {
+  return sf_parse_item(dest, begin, end);
+}
+
+static ssize_t sf_parse_inner_list(nghttp2_sf_value *dest, const uint8_t *begin,
+                                   const uint8_t *end) {
+  const uint8_t *p = begin;
+  ssize_t slen;
+
+  if (*p++ != '(') {
+    return -1;
+  }
+
+  for (;;) {
+    sf_discard_sp_end_err(p, end, -1);
+
+    if (*p == ')') {
+      ++p;
+
+      slen = sf_parse_params(p, end);
+      if (slen < 0) {
+        return -1;
+      }
+
+      p += slen;
+
+      if (dest) {
+        dest->type = NGHTTP2_SF_VALUE_TYPE_INNER_LIST;
+      }
+
+      return p - begin;
+    }
+
+    slen = sf_parse_item(NULL, p, end);
+    if (slen < 0) {
+      return -1;
+    }
+
+    p += slen;
+
+    if (p == end || (*p != ' ' && *p != ')')) {
+      return -1;
+    }
+  }
+}
+
+ssize_t nghttp2_sf_parse_inner_list(nghttp2_sf_value *dest,
+                                    const uint8_t *begin, const uint8_t *end) {
+  return sf_parse_inner_list(dest, begin, end);
+}
+
+static ssize_t sf_parse_item_or_inner_list(nghttp2_sf_value *dest,
+                                           const uint8_t *begin,
+                                           const uint8_t *end) {
+  if (*begin == '(') {
+    return sf_parse_inner_list(dest, begin, end);
+  }
+
+  return sf_parse_item(dest, begin, end);
+}
+
+#define sf_discard_ows(BEGIN, END)                                             \
+  for (;; ++(BEGIN)) {                                                         \
+    if ((BEGIN) == (END)) {                                                    \
+      goto fin;                                                                \
+    }                                                                          \
+    if (*(BEGIN) != ' ' && *(BEGIN) != '\t') {                                 \
+      break;                                                                   \
+    }                                                                          \
+  }
+
+#define sf_discard_ows_end_err(BEGIN, END, ERR)                                \
+  for (;; ++(BEGIN)) {                                                         \
+    if ((BEGIN) == (END)) {                                                    \
+      return (ERR);                                                            \
+    }                                                                          \
+    if (*(BEGIN) != ' ' && *(BEGIN) != '\t') {                                 \
+      break;                                                                   \
+    }                                                                          \
+  }
+
+int nghttp2_http_parse_priority(nghttp2_extpri *dest, const uint8_t *value,
+                                size_t valuelen) {
+  const uint8_t *p = value, *end = value + valuelen;
+  ssize_t slen;
+  nghttp2_sf_value val;
+  nghttp2_extpri pri = *dest;
+  const uint8_t *key;
+  size_t keylen;
+
+  for (; p != end && *p == ' '; ++p)
+    ;
+
+  for (; p != end;) {
+    slen = sf_parse_key(p, end);
+    if (slen < 0) {
+      return NGHTTP2_ERR_INVALID_ARGUMENT;
+    }
+
+    key = p;
+    keylen = (size_t)slen;
+
+    p += slen;
+
+    if (p == end || *p != '=') {
+      /* Boolean true */
+      val.type = NGHTTP2_SF_VALUE_TYPE_BOOLEAN;
+      val.b = 1;
+
+      slen = sf_parse_params(p, end);
+      if (slen < 0) {
+        return NGHTTP2_ERR_INVALID_ARGUMENT;
+      }
+    } else if (++p == end) {
+      return NGHTTP2_ERR_INVALID_ARGUMENT;
+    } else {
+      slen = sf_parse_item_or_inner_list(&val, p, end);
+      if (slen < 0) {
+        return NGHTTP2_ERR_INVALID_ARGUMENT;
+      }
+    }
+
+    p += slen;
+
+    if (keylen == 1) {
+      switch (key[0]) {
+      case 'i':
+        if (val.type != NGHTTP2_SF_VALUE_TYPE_BOOLEAN) {
+          return NGHTTP2_ERR_INVALID_ARGUMENT;
+        }
+
+        pri.inc = val.b;
+
+        break;
+      case 'u':
+        if (val.type != NGHTTP2_SF_VALUE_TYPE_INTEGER ||
+            val.i < NGHTTP2_EXTPRI_URGENCY_HIGH ||
+            NGHTTP2_EXTPRI_URGENCY_LOW < val.i) {
+          return NGHTTP2_ERR_INVALID_ARGUMENT;
+        }
+
+        pri.urgency = (uint32_t)val.i;
+
+        break;
+      }
+    }
+
+    sf_discard_ows(p, end);
+
+    if (*p++ != ',') {
+      return NGHTTP2_ERR_INVALID_ARGUMENT;
+    }
+
+    sf_discard_ows_end_err(p, end, NGHTTP2_ERR_INVALID_ARGUMENT);
+  }
+
+fin:
+  *dest = pri;
+
+  return 0;
+}
diff --git a/Utilities/cmnghttp2/lib/nghttp2_http.h b/Utilities/cmnghttp2/lib/nghttp2_http.h
index dd057cdb60..0c3a78eeef 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_http.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_http.h
@@ -94,4 +94,55 @@ int nghttp2_http_on_data_chunk(nghttp2_stream *stream, size_t n);
 void nghttp2_http_record_request_method(nghttp2_stream *stream,
                                         nghttp2_frame *frame);
 
+/*
+ * RFC 8941 Structured Field Values.
+ */
+typedef enum nghttp2_sf_value_type {
+  NGHTTP2_SF_VALUE_TYPE_BOOLEAN,
+  NGHTTP2_SF_VALUE_TYPE_INTEGER,
+  NGHTTP2_SF_VALUE_TYPE_DECIMAL,
+  NGHTTP2_SF_VALUE_TYPE_STRING,
+  NGHTTP2_SF_VALUE_TYPE_TOKEN,
+  NGHTTP2_SF_VALUE_TYPE_BYTESEQ,
+  NGHTTP2_SF_VALUE_TYPE_INNER_LIST,
+} nghttp2_sf_value_type;
+
+/*
+ * nghttp2_sf_value stores Structured Field Values item.  For Inner
+ * List, only type is set to NGHTTP2_SF_VALUE_TYPE_INNER_LIST.
+ */
+typedef struct nghttp2_sf_value {
+  uint8_t type;
+  union {
+    int b;
+    int64_t i;
+    double d;
+    struct {
+      const uint8_t *base;
+      size_t len;
+    } s;
+  };
+} nghttp2_sf_value;
+
+/*
+ * nghttp2_sf_parse_item parses the input sequence [|begin|, |end|)
+ * and stores the parsed an Item in |dest|.  It returns the number of
+ * bytes consumed if it succeeds, or -1.  This function is declared
+ * here for unit tests.
+ */
+ssize_t nghttp2_sf_parse_item(nghttp2_sf_value *dest, const uint8_t *begin,
+                              const uint8_t *end);
+
+/*
+ * nghttp2_sf_parse_inner_list parses the input sequence [|begin|, |end|)
+ * and stores the parsed an Inner List in |dest|.  It returns the number of
+ * bytes consumed if it succeeds, or -1.  This function is declared
+ * here for unit tests.
+ */
+ssize_t nghttp2_sf_parse_inner_list(nghttp2_sf_value *dest,
+                                    const uint8_t *begin, const uint8_t *end);
+
+int nghttp2_http_parse_priority(nghttp2_extpri *dest, const uint8_t *value,
+                                size_t valuelen);
+
 #endif /* NGHTTP2_HTTP_H */
diff --git a/Utilities/cmnghttp2/lib/nghttp2_map.c b/Utilities/cmnghttp2/lib/nghttp2_map.c
index 4d9f97b47e..e5db168ca2 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_map.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_map.c
@@ -1,7 +1,8 @@
 /*
  * nghttp2 - HTTP/2 C Library
  *
- * Copyright (c) 2012 Tatsuhiro Tsujikawa
+ * Copyright (c) 2017 ngtcp2 contributors
+ * Copyright (c) 2012 nghttp2 contributors
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -25,14 +26,19 @@
 #include "nghttp2_map.h"
 
 #include <string.h>
+#include <assert.h>
+#include <stdio.h>
 
-#define INITIAL_TABLE_LENGTH 256
+#include "nghttp2_helper.h"
+
+#define NGHTTP2_INITIAL_TABLE_LENBITS 8
 
 int nghttp2_map_init(nghttp2_map *map, nghttp2_mem *mem) {
   map->mem = mem;
-  map->tablelen = INITIAL_TABLE_LENGTH;
+  map->tablelen = 1 << NGHTTP2_INITIAL_TABLE_LENBITS;
+  map->tablelenbits = NGHTTP2_INITIAL_TABLE_LENBITS;
   map->table =
-      nghttp2_mem_calloc(mem, map->tablelen, sizeof(nghttp2_map_entry *));
+      nghttp2_mem_calloc(mem, map->tablelen, sizeof(nghttp2_map_bucket));
   if (map->table == NULL) {
     return NGHTTP2_ERR_NOMEM;
   }
@@ -43,112 +49,188 @@ int nghttp2_map_init(nghttp2_map *map, nghttp2_mem *mem) {
 }
 
 void nghttp2_map_free(nghttp2_map *map) {
+  if (!map) {
+    return;
+  }
+
   nghttp2_mem_free(map->mem, map->table);
 }
 
-void nghttp2_map_each_free(nghttp2_map *map,
-                           int (*func)(nghttp2_map_entry *entry, void *ptr),
+void nghttp2_map_each_free(nghttp2_map *map, int (*func)(void *data, void *ptr),
                            void *ptr) {
   uint32_t i;
+  nghttp2_map_bucket *bkt;
+
   for (i = 0; i < map->tablelen; ++i) {
-    nghttp2_map_entry *entry;
-    for (entry = map->table[i]; entry;) {
-      nghttp2_map_entry *next = entry->next;
-      func(entry, ptr);
-      entry = next;
+    bkt = &map->table[i];
+
+    if (bkt->data == NULL) {
+      continue;
     }
-    map->table[i] = NULL;
+
+    func(bkt->data, ptr);
   }
 }
 
-int nghttp2_map_each(nghttp2_map *map,
-                     int (*func)(nghttp2_map_entry *entry, void *ptr),
+int nghttp2_map_each(nghttp2_map *map, int (*func)(void *data, void *ptr),
                      void *ptr) {
   int rv;
   uint32_t i;
+  nghttp2_map_bucket *bkt;
+
   for (i = 0; i < map->tablelen; ++i) {
-    nghttp2_map_entry *entry;
-    for (entry = map->table[i]; entry; entry = entry->next) {
-      rv = func(entry, ptr);
-      if (rv != 0) {
-        return rv;
-      }
+    bkt = &map->table[i];
+
+    if (bkt->data == NULL) {
+      continue;
+    }
+
+    rv = func(bkt->data, ptr);
+    if (rv != 0) {
+      return rv;
     }
   }
+
   return 0;
 }
 
-void nghttp2_map_entry_init(nghttp2_map_entry *entry, key_type key) {
-  entry->key = key;
-  entry->next = NULL;
+static uint32_t hash(nghttp2_map_key_type key) {
+  return (uint32_t)key * 2654435769u;
 }
 
-/* Same hash function in android HashMap source code. */
-/* The |mod| must be power of 2 */
-static uint32_t hash(int32_t key, uint32_t mod) {
-  uint32_t h = (uint32_t)key;
-  h ^= (h >> 20) ^ (h >> 12);
-  h ^= (h >> 7) ^ (h >> 4);
-  return h & (mod - 1);
+static size_t h2idx(uint32_t hash, uint32_t bits) {
+  return hash >> (32 - bits);
 }
 
-static int insert(nghttp2_map_entry **table, uint32_t tablelen,
-                  nghttp2_map_entry *entry) {
-  uint32_t h = hash(entry->key, tablelen);
-  if (table[h] == NULL) {
-    table[h] = entry;
-  } else {
-    nghttp2_map_entry *p;
-    /* We won't allow duplicated key, so check it out. */
-    for (p = table[h]; p; p = p->next) {
-      if (p->key == entry->key) {
-        return NGHTTP2_ERR_INVALID_ARGUMENT;
-      }
+static size_t distance(uint32_t tablelen, uint32_t tablelenbits,
+                       nghttp2_map_bucket *bkt, size_t idx) {
+  return (idx - h2idx(bkt->hash, tablelenbits)) & (tablelen - 1);
+}
+
+static void map_bucket_swap(nghttp2_map_bucket *bkt, uint32_t *phash,
+                            nghttp2_map_key_type *pkey, void **pdata) {
+  uint32_t h = bkt->hash;
+  nghttp2_map_key_type key = bkt->key;
+  void *data = bkt->data;
+
+  bkt->hash = *phash;
+  bkt->key = *pkey;
+  bkt->data = *pdata;
+
+  *phash = h;
+  *pkey = key;
+  *pdata = data;
+}
+
+static void map_bucket_set_data(nghttp2_map_bucket *bkt, uint32_t hash,
+                                nghttp2_map_key_type key, void *data) {
+  bkt->hash = hash;
+  bkt->key = key;
+  bkt->data = data;
+}
+
+void nghttp2_map_print_distance(nghttp2_map *map) {
+  uint32_t i;
+  size_t idx;
+  nghttp2_map_bucket *bkt;
+
+  for (i = 0; i < map->tablelen; ++i) {
+    bkt = &map->table[i];
+
+    if (bkt->data == NULL) {
+      fprintf(stderr, "@%u <EMPTY>\n", i);
+      continue;
     }
-    entry->next = table[h];
-    table[h] = entry;
+
+    idx = h2idx(bkt->hash, map->tablelenbits);
+    fprintf(stderr, "@%u hash=%08x key=%d base=%zu distance=%zu\n", i,
+            bkt->hash, bkt->key, idx,
+            distance(map->tablelen, map->tablelenbits, bkt, idx));
+  }
+}
+
+static int insert(nghttp2_map_bucket *table, uint32_t tablelen,
+                  uint32_t tablelenbits, uint32_t hash,
+                  nghttp2_map_key_type key, void *data) {
+  size_t idx = h2idx(hash, tablelenbits);
+  size_t d = 0, dd;
+  nghttp2_map_bucket *bkt;
+
+  for (;;) {
+    bkt = &table[idx];
+
+    if (bkt->data == NULL) {
+      map_bucket_set_data(bkt, hash, key, data);
+      return 0;
+    }
+
+    dd = distance(tablelen, tablelenbits, bkt, idx);
+    if (d > dd) {
+      map_bucket_swap(bkt, &hash, &key, &data);
+      d = dd;
+    } else if (bkt->key == key) {
+      /* TODO This check is just a waste after first swap or if this
+         function is called from map_resize.  That said, there is no
+         difference with or without this conditional in performance
+         wise. */
+      return NGHTTP2_ERR_INVALID_ARGUMENT;
+    }
+
+    ++d;
+    idx = (idx + 1) & (tablelen - 1);
   }
-  return 0;
 }
 
-/* new_tablelen must be power of 2 */
-static int resize(nghttp2_map *map, uint32_t new_tablelen) {
+/* new_tablelen must be power of 2 and new_tablelen == (1 <<
+   new_tablelenbits) must hold. */
+static int map_resize(nghttp2_map *map, uint32_t new_tablelen,
+                      uint32_t new_tablelenbits) {
   uint32_t i;
-  nghttp2_map_entry **new_table;
+  nghttp2_map_bucket *new_table;
+  nghttp2_map_bucket *bkt;
+  int rv;
+  (void)rv;
 
   new_table =
-      nghttp2_mem_calloc(map->mem, new_tablelen, sizeof(nghttp2_map_entry *));
+      nghttp2_mem_calloc(map->mem, new_tablelen, sizeof(nghttp2_map_bucket));
   if (new_table == NULL) {
     return NGHTTP2_ERR_NOMEM;
   }
 
   for (i = 0; i < map->tablelen; ++i) {
-    nghttp2_map_entry *entry;
-    for (entry = map->table[i]; entry;) {
-      nghttp2_map_entry *next = entry->next;
-      entry->next = NULL;
-      /* This function must succeed */
-      insert(new_table, new_tablelen, entry);
-      entry = next;
+    bkt = &map->table[i];
+    if (bkt->data == NULL) {
+      continue;
     }
+    rv = insert(new_table, new_tablelen, new_tablelenbits, bkt->hash, bkt->key,
+                bkt->data);
+
+    assert(0 == rv);
   }
+
   nghttp2_mem_free(map->mem, map->table);
   map->tablelen = new_tablelen;
+  map->tablelenbits = new_tablelenbits;
   map->table = new_table;
 
   return 0;
 }
 
-int nghttp2_map_insert(nghttp2_map *map, nghttp2_map_entry *new_entry) {
+int nghttp2_map_insert(nghttp2_map *map, nghttp2_map_key_type key, void *data) {
   int rv;
+
+  assert(data);
+
   /* Load factor is 0.75 */
   if ((map->size + 1) * 4 > map->tablelen * 3) {
-    rv = resize(map, map->tablelen * 2);
+    rv = map_resize(map, map->tablelen * 2, map->tablelenbits + 1);
     if (rv != 0) {
       return rv;
     }
   }
-  rv = insert(map->table, map->tablelen, new_entry);
+
+  rv = insert(map->table, map->tablelen, map->tablelenbits, hash(key), key,
+              data);
   if (rv != 0) {
     return rv;
   }
@@ -156,34 +238,76 @@ int nghttp2_map_insert(nghttp2_map *map, nghttp2_map_entry *new_entry) {
   return 0;
 }
 
-nghttp2_map_entry *nghttp2_map_find(nghttp2_map *map, key_type key) {
-  uint32_t h;
-  nghttp2_map_entry *entry;
-  h = hash(key, map->tablelen);
-  for (entry = map->table[h]; entry; entry = entry->next) {
-    if (entry->key == key) {
-      return entry;
+void *nghttp2_map_find(nghttp2_map *map, nghttp2_map_key_type key) {
+  uint32_t h = hash(key);
+  size_t idx = h2idx(h, map->tablelenbits);
+  nghttp2_map_bucket *bkt;
+  size_t d = 0;
+
+  for (;;) {
+    bkt = &map->table[idx];
+
+    if (bkt->data == NULL ||
+        d > distance(map->tablelen, map->tablelenbits, bkt, idx)) {
+      return NULL;
     }
+
+    if (bkt->key == key) {
+      return bkt->data;
+    }
+
+    ++d;
+    idx = (idx + 1) & (map->tablelen - 1);
   }
-  return NULL;
 }
 
-int nghttp2_map_remove(nghttp2_map *map, key_type key) {
-  uint32_t h;
-  nghttp2_map_entry **dst;
+int nghttp2_map_remove(nghttp2_map *map, nghttp2_map_key_type key) {
+  uint32_t h = hash(key);
+  size_t idx = h2idx(h, map->tablelenbits), didx;
+  nghttp2_map_bucket *bkt;
+  size_t d = 0;
 
-  h = hash(key, map->tablelen);
+  for (;;) {
+    bkt = &map->table[idx];
 
-  for (dst = &map->table[h]; *dst; dst = &(*dst)->next) {
-    if ((*dst)->key != key) {
-      continue;
+    if (bkt->data == NULL ||
+        d > distance(map->tablelen, map->tablelenbits, bkt, idx)) {
+      return NGHTTP2_ERR_INVALID_ARGUMENT;
+    }
+
+    if (bkt->key == key) {
+      map_bucket_set_data(bkt, 0, 0, NULL);
+
+      didx = idx;
+      idx = (idx + 1) & (map->tablelen - 1);
+
+      for (;;) {
+        bkt = &map->table[idx];
+        if (bkt->data == NULL ||
+            distance(map->tablelen, map->tablelenbits, bkt, idx) == 0) {
+          break;
+        }
+
+        map->table[didx] = *bkt;
+        map_bucket_set_data(bkt, 0, 0, NULL);
+        didx = idx;
+
+        idx = (idx + 1) & (map->tablelen - 1);
+      }
+
+      --map->size;
+
+      return 0;
     }
 
-    *dst = (*dst)->next;
-    --map->size;
-    return 0;
+    ++d;
+    idx = (idx + 1) & (map->tablelen - 1);
   }
-  return NGHTTP2_ERR_INVALID_ARGUMENT;
+}
+
+void nghttp2_map_clear(nghttp2_map *map) {
+  memset(map->table, 0, sizeof(*map->table) * map->tablelen);
+  map->size = 0;
 }
 
 size_t nghttp2_map_size(nghttp2_map *map) { return map->size; }
diff --git a/Utilities/cmnghttp2/lib/nghttp2_map.h b/Utilities/cmnghttp2/lib/nghttp2_map.h
index f6e29e35f2..1419a09a35 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_map.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_map.h
@@ -1,7 +1,8 @@
 /*
  * nghttp2 - HTTP/2 C Library
  *
- * Copyright (c) 2012 Tatsuhiro Tsujikawa
+ * Copyright (c) 2017 ngtcp2 contributors
+ * Copyright (c) 2012 nghttp2 contributors
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -30,27 +31,25 @@
 #endif /* HAVE_CONFIG_H */
 
 #include <nghttp2/nghttp2.h>
-#include "nghttp2_int.h"
+
 #include "nghttp2_mem.h"
 
 /* Implementation of unordered map */
 
-typedef int32_t key_type;
+typedef int32_t nghttp2_map_key_type;
 
-typedef struct nghttp2_map_entry {
-  struct nghttp2_map_entry *next;
-  key_type key;
-#if SIZEOF_INT_P == 4
-  /* we requires 8 bytes aligment */
-  int64_t pad;
-#endif
-} nghttp2_map_entry;
+typedef struct nghttp2_map_bucket {
+  uint32_t hash;
+  nghttp2_map_key_type key;
+  void *data;
+} nghttp2_map_bucket;
 
-typedef struct {
-  nghttp2_map_entry **table;
+typedef struct nghttp2_map {
+  nghttp2_map_bucket *table;
   nghttp2_mem *mem;
   size_t size;
   uint32_t tablelen;
+  uint32_t tablelenbits;
 } nghttp2_map;
 
 /*
@@ -74,21 +73,14 @@ void nghttp2_map_free(nghttp2_map *map);
 /*
  * Deallocates each entries using |func| function and any resources
  * allocated for |map|. The |func| function is responsible for freeing
- * given the |entry| object. The |ptr| will be passed to the |func| as
+ * given the |data| object. The |ptr| will be passed to the |func| as
  * send argument. The return value of the |func| will be ignored.
  */
-void nghttp2_map_each_free(nghttp2_map *map,
-                           int (*func)(nghttp2_map_entry *entry, void *ptr),
+void nghttp2_map_each_free(nghttp2_map *map, int (*func)(void *data, void *ptr),
                            void *ptr);
 
 /*
- * Initializes the |entry| with the |key|. All entries to be inserted
- * to the map must be initialized with this function.
- */
-void nghttp2_map_entry_init(nghttp2_map_entry *entry, key_type key);
-
-/*
- * Inserts the new |entry| with the key |entry->key| to the map |map|.
+ * Inserts the new |data| with the |key| to the map |map|.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
@@ -98,25 +90,30 @@ void nghttp2_map_entry_init(nghttp2_map_entry *entry, key_type key);
  * NGHTTP2_ERR_NOMEM
  *   Out of memory
  */
-int nghttp2_map_insert(nghttp2_map *map, nghttp2_map_entry *entry);
+int nghttp2_map_insert(nghttp2_map *map, nghttp2_map_key_type key, void *data);
 
 /*
- * Returns the entry associated by the key |key|.  If there is no such
- * entry, this function returns NULL.
+ * Returns the data associated by the key |key|.  If there is no such
+ * data, this function returns NULL.
  */
-nghttp2_map_entry *nghttp2_map_find(nghttp2_map *map, key_type key);
+void *nghttp2_map_find(nghttp2_map *map, nghttp2_map_key_type key);
 
 /*
- * Removes the entry associated by the key |key| from the |map|.  The
- * removed entry is not freed by this function.
+ * Removes the data associated by the key |key| from the |map|.  The
+ * removed data is not freed by this function.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
  * NGHTTP2_ERR_INVALID_ARGUMENT
- *     The entry associated by |key| does not exist.
+ *     The data associated by |key| does not exist.
  */
-int nghttp2_map_remove(nghttp2_map *map, key_type key);
+int nghttp2_map_remove(nghttp2_map *map, nghttp2_map_key_type key);
+
+/*
+ * Removes all entries from |map|.
+ */
+void nghttp2_map_clear(nghttp2_map *map);
 
 /*
  * Returns the number of items stored in the map |map|.
@@ -124,21 +121,22 @@ int nghttp2_map_remove(nghttp2_map *map, key_type key);
 size_t nghttp2_map_size(nghttp2_map *map);
 
 /*
- * Applies the function |func| to each entry in the |map| with the
+ * Applies the function |func| to each data in the |map| with the
  * optional user supplied pointer |ptr|.
  *
  * If the |func| returns 0, this function calls the |func| with the
- * next entry. If the |func| returns nonzero, it will not call the
+ * next data.  If the |func| returns nonzero, it will not call the
  * |func| for further entries and return the return value of the
  * |func| immediately.  Thus, this function returns 0 if all the
  * invocations of the |func| return 0, or nonzero value which the last
  * invocation of |func| returns.
  *
- * Don't use this function to free each entry. Use
+ * Don't use this function to free each data. Use
  * nghttp2_map_each_free() instead.
  */
-int nghttp2_map_each(nghttp2_map *map,
-                     int (*func)(nghttp2_map_entry *entry, void *ptr),
+int nghttp2_map_each(nghttp2_map *map, int (*func)(void *data, void *ptr),
                      void *ptr);
 
+void nghttp2_map_print_distance(nghttp2_map *map);
+
 #endif /* NGHTTP2_MAP_H */
diff --git a/Utilities/cmnghttp2/lib/nghttp2_net.h b/Utilities/cmnghttp2/lib/nghttp2_net.h
index 95ffee74a1..345f6c834f 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_net.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_net.h
@@ -42,7 +42,7 @@
 #if defined(WIN32)
 /* Windows requires ws2_32 library for ntonl family functions.  We
    define inline functions for those function so that we don't have
-   dependeny on that lib. */
+   dependency on that lib. */
 
 #  ifdef _MSC_VER
 #    define STIN static __inline
@@ -53,7 +53,7 @@
 STIN uint32_t htonl(uint32_t hostlong) {
   uint32_t res;
   unsigned char *p = (unsigned char *)&res;
-  *p++ = hostlong >> 24;
+  *p++ = (unsigned char)(hostlong >> 24);
   *p++ = (hostlong >> 16) & 0xffu;
   *p++ = (hostlong >> 8) & 0xffu;
   *p = hostlong & 0xffu;
@@ -63,7 +63,7 @@ STIN uint32_t htonl(uint32_t hostlong) {
 STIN uint16_t htons(uint16_t hostshort) {
   uint16_t res;
   unsigned char *p = (unsigned char *)&res;
-  *p++ = hostshort >> 8;
+  *p++ = (unsigned char)(hostshort >> 8);
   *p = hostshort & 0xffu;
   return res;
 }
diff --git a/Utilities/cmnghttp2/lib/nghttp2_option.c b/Utilities/cmnghttp2/lib/nghttp2_option.c
index e53f22d367..ee0cd0f022 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_option.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_option.c
@@ -90,6 +90,10 @@ void nghttp2_option_set_builtin_recv_extension_type(nghttp2_option *option,
     option->opt_set_mask |= NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES;
     option->builtin_recv_ext_types |= NGHTTP2_TYPEMASK_ORIGIN;
     return;
+  case NGHTTP2_PRIORITY_UPDATE:
+    option->opt_set_mask |= NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES;
+    option->builtin_recv_ext_types |= NGHTTP2_TYPEMASK_PRIORITY_UPDATE;
+    return;
   default:
     return;
   }
@@ -121,3 +125,21 @@ void nghttp2_option_set_max_outbound_ack(nghttp2_option *option, size_t val) {
   option->opt_set_mask |= NGHTTP2_OPT_MAX_OUTBOUND_ACK;
   option->max_outbound_ack = val;
 }
+
+void nghttp2_option_set_max_settings(nghttp2_option *option, size_t val) {
+  option->opt_set_mask |= NGHTTP2_OPT_MAX_SETTINGS;
+  option->max_settings = val;
+}
+
+void nghttp2_option_set_server_fallback_rfc7540_priorities(
+    nghttp2_option *option, int val) {
+  option->opt_set_mask |= NGHTTP2_OPT_SERVER_FALLBACK_RFC7540_PRIORITIES;
+  option->server_fallback_rfc7540_priorities = val;
+}
+
+void nghttp2_option_set_no_rfc9113_leading_and_trailing_ws_validation(
+    nghttp2_option *option, int val) {
+  option->opt_set_mask |=
+      NGHTTP2_OPT_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION;
+  option->no_rfc9113_leading_and_trailing_ws_validation = val;
+}
diff --git a/Utilities/cmnghttp2/lib/nghttp2_option.h b/Utilities/cmnghttp2/lib/nghttp2_option.h
index 1f740aaa6e..b228a0754c 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_option.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_option.h
@@ -67,6 +67,9 @@ typedef enum {
   NGHTTP2_OPT_MAX_DEFLATE_DYNAMIC_TABLE_SIZE = 1 << 9,
   NGHTTP2_OPT_NO_CLOSED_STREAMS = 1 << 10,
   NGHTTP2_OPT_MAX_OUTBOUND_ACK = 1 << 11,
+  NGHTTP2_OPT_MAX_SETTINGS = 1 << 12,
+  NGHTTP2_OPT_SERVER_FALLBACK_RFC7540_PRIORITIES = 1 << 13,
+  NGHTTP2_OPT_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION = 1 << 14,
 } nghttp2_option_flag;
 
 /**
@@ -86,6 +89,10 @@ struct nghttp2_option {
    */
   size_t max_outbound_ack;
   /**
+   * NGHTTP2_OPT_MAX_SETTINGS
+   */
+  size_t max_settings;
+  /**
    * Bitwise OR of nghttp2_option_flag to determine that which fields
    * are specified.
    */
@@ -123,6 +130,14 @@ struct nghttp2_option {
    */
   int no_closed_streams;
   /**
+   * NGHTTP2_OPT_SERVER_FALLBACK_RFC7540_PRIORITIES
+   */
+  int server_fallback_rfc7540_priorities;
+  /**
+   * NGHTTP2_OPT_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION
+   */
+  int no_rfc9113_leading_and_trailing_ws_validation;
+  /**
    * NGHTTP2_OPT_USER_RECV_EXT_TYPES
    */
   uint8_t user_recv_ext_types[32];
diff --git a/Utilities/cmnghttp2/lib/nghttp2_outbound_item.c b/Utilities/cmnghttp2/lib/nghttp2_outbound_item.c
index f651c8029a..2a3041db19 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_outbound_item.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_outbound_item.c
@@ -89,6 +89,9 @@ void nghttp2_outbound_item_free(nghttp2_outbound_item *item, nghttp2_mem *mem) {
     case NGHTTP2_ORIGIN:
       nghttp2_frame_origin_free(&frame->ext, mem);
       break;
+    case NGHTTP2_PRIORITY_UPDATE:
+      nghttp2_frame_priority_update_free(&frame->ext, mem);
+      break;
     default:
       assert(0);
       break;
diff --git a/Utilities/cmnghttp2/lib/nghttp2_outbound_item.h b/Utilities/cmnghttp2/lib/nghttp2_outbound_item.h
index b5f503a312..bd4611b551 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_outbound_item.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_outbound_item.h
@@ -111,7 +111,7 @@ struct nghttp2_outbound_item {
      to this structure to avoid frequent memory allocation. */
   nghttp2_ext_frame_payload ext_frame_payload;
   nghttp2_aux_data aux_data;
-  /* The priority used in priority comparion.  Smaller is served
+  /* The priority used in priority comparison.  Smaller is served
      earlier.  For PING, SETTINGS and non-DATA frames (excluding
      response HEADERS frame) have dedicated cycle value defined above.
      For DATA frame, cycle is computed by taking into account of
diff --git a/Utilities/cmnghttp2/lib/nghttp2_pq.c b/Utilities/cmnghttp2/lib/nghttp2_pq.c
index bebccc7606..64353acc96 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_pq.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_pq.c
@@ -29,13 +29,12 @@
 
 #include "nghttp2_helper.h"
 
-int nghttp2_pq_init(nghttp2_pq *pq, nghttp2_less less, nghttp2_mem *mem) {
+void nghttp2_pq_init(nghttp2_pq *pq, nghttp2_less less, nghttp2_mem *mem) {
   pq->mem = mem;
   pq->capacity = 0;
   pq->q = NULL;
   pq->length = 0;
   pq->less = less;
-  return 0;
 }
 
 void nghttp2_pq_free(nghttp2_pq *pq) {
diff --git a/Utilities/cmnghttp2/lib/nghttp2_pq.h b/Utilities/cmnghttp2/lib/nghttp2_pq.h
index 2d7b702ac1..c8d90ef2cc 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_pq.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_pq.h
@@ -55,14 +55,8 @@ typedef struct {
 
 /*
  * Initializes priority queue |pq| with compare function |cmp|.
- *
- * This function returns 0 if it succeeds, or one of the following
- * negative error codes:
- *
- * NGHTTP2_ERR_NOMEM
- *     Out of memory.
  */
-int nghttp2_pq_init(nghttp2_pq *pq, nghttp2_less less, nghttp2_mem *mem);
+void nghttp2_pq_init(nghttp2_pq *pq, nghttp2_less less, nghttp2_mem *mem);
 
 /*
  * Deallocates any resources allocated for |pq|.  The stored items are
@@ -114,7 +108,7 @@ typedef int (*nghttp2_pq_item_cb)(nghttp2_pq_entry *item, void *arg);
 void nghttp2_pq_update(nghttp2_pq *pq, nghttp2_pq_item_cb fun, void *arg);
 
 /*
- * Applys |fun| to each item in |pq|.  The |arg| is passed as arg
+ * Applies |fun| to each item in |pq|.  The |arg| is passed as arg
  * parameter to callback function.  This function must not change the
  * ordering key.  If the return value from callback is nonzero, this
  * function returns 1 immediately without iterating remaining items.
diff --git a/Utilities/cmnghttp2/lib/nghttp2_session.c b/Utilities/cmnghttp2/lib/nghttp2_session.c
index 9df3d6f329..93f3f07cf7 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_session.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_session.c
@@ -36,6 +36,7 @@
 #include "nghttp2_option.h"
 #include "nghttp2_http.h"
 #include "nghttp2_pq.h"
+#include "nghttp2_extpri.h"
 #include "nghttp2_debug.h"
 
 /*
@@ -143,6 +144,11 @@ static int session_detect_idle_stream(nghttp2_session *session,
   return 0;
 }
 
+static int session_no_rfc7540_pri_no_fallback(nghttp2_session *session) {
+  return session->pending_no_rfc7540_priorities == 1 &&
+         !session->fallback_rfc7540_priorities;
+}
+
 static int check_ext_type_set(const uint8_t *ext_types, uint8_t type) {
   return (ext_types[type / 8] & (1 << (type & 0x7))) > 0;
 }
@@ -354,6 +360,14 @@ static void session_inbound_frame_reset(nghttp2_session *session) {
         }
         nghttp2_frame_origin_free(&iframe->frame.ext, mem);
         break;
+      case NGHTTP2_PRIORITY_UPDATE:
+        if ((session->builtin_recv_ext_types &
+             NGHTTP2_TYPEMASK_PRIORITY_UPDATE) == 0) {
+          break;
+        }
+        /* Do not call nghttp2_frame_priority_update_free, because all
+           fields point to sbuf. */
+        break;
       }
     }
 
@@ -385,6 +399,7 @@ static void init_settings(nghttp2_settings_storage *settings) {
   settings->initial_window_size = NGHTTP2_INITIAL_WINDOW_SIZE;
   settings->max_frame_size = NGHTTP2_MAX_FRAME_SIZE_MIN;
   settings->max_header_list_size = UINT32_MAX;
+  settings->no_rfc7540_priorities = UINT32_MAX;
 }
 
 static void active_outbound_item_reset(nghttp2_active_outbound_item *aob,
@@ -398,6 +413,21 @@ static void active_outbound_item_reset(nghttp2_active_outbound_item *aob,
   aob->state = NGHTTP2_OB_POP_ITEM;
 }
 
+#define NGHTTP2_STREAM_MAX_CYCLE_GAP ((uint64_t)NGHTTP2_MAX_FRAME_SIZE_MAX)
+
+static int stream_less(const void *lhsx, const void *rhsx) {
+  const nghttp2_stream *lhs, *rhs;
+
+  lhs = nghttp2_struct_of(lhsx, nghttp2_stream, pq_entry);
+  rhs = nghttp2_struct_of(rhsx, nghttp2_stream, pq_entry);
+
+  if (lhs->cycle == rhs->cycle) {
+    return lhs->seq < rhs->seq;
+  }
+
+  return rhs->cycle - lhs->cycle <= NGHTTP2_STREAM_MAX_CYCLE_GAP;
+}
+
 int nghttp2_enable_strict_preface = 1;
 
 static int session_new(nghttp2_session **session_ptr,
@@ -408,6 +438,7 @@ static int session_new(nghttp2_session **session_ptr,
   size_t nbuffer;
   size_t max_deflate_dynamic_table_size =
       NGHTTP2_HD_DEFAULT_MAX_DEFLATE_BUFFER_SIZE;
+  size_t i;
 
   if (mem == NULL) {
     mem = nghttp2_mem_default();
@@ -442,6 +473,7 @@ static int session_new(nghttp2_session **session_ptr,
   (*session_ptr)->pending_local_max_concurrent_stream =
       NGHTTP2_DEFAULT_MAX_CONCURRENT_STREAMS;
   (*session_ptr)->pending_enable_push = 1;
+  (*session_ptr)->pending_no_rfc7540_priorities = UINT8_MAX;
 
   if (server) {
     (*session_ptr)->server = 1;
@@ -458,6 +490,7 @@ static int session_new(nghttp2_session **session_ptr,
 
   (*session_ptr)->max_send_header_block_length = NGHTTP2_MAX_HEADERSLEN;
   (*session_ptr)->max_outbound_ack = NGHTTP2_DEFAULT_MAX_OBQ_FLOOD_ITEM;
+  (*session_ptr)->max_settings = NGHTTP2_DEFAULT_MAX_SETTINGS;
 
   if (option) {
     if ((option->opt_set_mask & NGHTTP2_OPT_NO_AUTO_WINDOW_UPDATE) &&
@@ -521,6 +554,25 @@ static int session_new(nghttp2_session **session_ptr,
     if (option->opt_set_mask & NGHTTP2_OPT_MAX_OUTBOUND_ACK) {
       (*session_ptr)->max_outbound_ack = option->max_outbound_ack;
     }
+
+    if ((option->opt_set_mask & NGHTTP2_OPT_MAX_SETTINGS) &&
+        option->max_settings) {
+      (*session_ptr)->max_settings = option->max_settings;
+    }
+
+    if ((option->opt_set_mask &
+         NGHTTP2_OPT_SERVER_FALLBACK_RFC7540_PRIORITIES) &&
+        option->server_fallback_rfc7540_priorities) {
+      (*session_ptr)->opt_flags |=
+          NGHTTP2_OPTMASK_SERVER_FALLBACK_RFC7540_PRIORITIES;
+    }
+
+    if ((option->opt_set_mask &
+         NGHTTP2_OPT_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION) &&
+        option->no_rfc9113_leading_and_trailing_ws_validation) {
+      (*session_ptr)->opt_flags |=
+          NGHTTP2_OPTMASK_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION;
+    }
   }
 
   rv = nghttp2_hd_deflate_init2(&(*session_ptr)->hd_deflater,
@@ -578,6 +630,10 @@ static int session_new(nghttp2_session **session_ptr,
     }
   }
 
+  for (i = 0; i < NGHTTP2_EXTPRI_URGENCY_LEVELS; ++i) {
+    nghttp2_pq_init(&(*session_ptr)->sched[i].ob_data, stream_less, mem);
+  }
+
   return 0;
 
 fail_aob_framebuf:
@@ -660,7 +716,7 @@ int nghttp2_session_server_new3(nghttp2_session **session_ptr,
   return 0;
 }
 
-static int free_streams(nghttp2_map_entry *entry, void *ptr) {
+static int free_streams(void *entry, void *ptr) {
   nghttp2_session *session;
   nghttp2_stream *stream;
   nghttp2_outbound_item *item;
@@ -729,6 +785,7 @@ static void inflight_settings_del(nghttp2_inflight_settings *settings,
 void nghttp2_session_del(nghttp2_session *session) {
   nghttp2_mem *mem;
   nghttp2_inflight_settings *settings;
+  size_t i;
 
   if (session == NULL) {
     return;
@@ -742,6 +799,9 @@ void nghttp2_session_del(nghttp2_session *session) {
     settings = next;
   }
 
+  for (i = 0; i < NGHTTP2_EXTPRI_URGENCY_LEVELS; ++i) {
+    nghttp2_pq_free(&session->sched[i].ob_data);
+  }
   nghttp2_stream_free(&session->root);
 
   /* Have to free streams first, so that we can check
@@ -769,6 +829,8 @@ int nghttp2_session_reprioritize_stream(
   nghttp2_priority_spec pri_spec_default;
   const nghttp2_priority_spec *pri_spec = pri_spec_in;
 
+  assert((!session->server && session->pending_no_rfc7540_priorities != 1) ||
+         (session->server && !session_no_rfc7540_pri_no_fallback(session)));
   assert(pri_spec->stream_id != stream->stream_id);
 
   if (!nghttp2_stream_in_dep_tree(stream)) {
@@ -836,6 +898,214 @@ int nghttp2_session_reprioritize_stream(
   return 0;
 }
 
+static uint64_t pq_get_first_cycle(nghttp2_pq *pq) {
+  nghttp2_stream *stream;
+
+  if (nghttp2_pq_empty(pq)) {
+    return 0;
+  }
+
+  stream = nghttp2_struct_of(nghttp2_pq_top(pq), nghttp2_stream, pq_entry);
+  return stream->cycle;
+}
+
+static int session_ob_data_push(nghttp2_session *session,
+                                nghttp2_stream *stream) {
+  int rv;
+  uint32_t urgency;
+  int inc;
+  nghttp2_pq *pq;
+
+  assert(stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES);
+  assert(stream->queued == 0);
+
+  urgency = nghttp2_extpri_uint8_urgency(stream->extpri);
+  inc = nghttp2_extpri_uint8_inc(stream->extpri);
+
+  assert(urgency < NGHTTP2_EXTPRI_URGENCY_LEVELS);
+
+  pq = &session->sched[urgency].ob_data;
+
+  stream->cycle = pq_get_first_cycle(pq);
+  if (inc) {
+    stream->cycle += stream->last_writelen;
+  }
+
+  rv = nghttp2_pq_push(pq, &stream->pq_entry);
+  if (rv != 0) {
+    return rv;
+  }
+
+  stream->queued = 1;
+
+  return 0;
+}
+
+static int session_ob_data_remove(nghttp2_session *session,
+                                  nghttp2_stream *stream) {
+  uint32_t urgency;
+
+  assert(stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES);
+  assert(stream->queued == 1);
+
+  urgency = nghttp2_extpri_uint8_urgency(stream->extpri);
+
+  assert(urgency < NGHTTP2_EXTPRI_URGENCY_LEVELS);
+
+  nghttp2_pq_remove(&session->sched[urgency].ob_data, &stream->pq_entry);
+
+  stream->queued = 0;
+
+  return 0;
+}
+
+static int session_attach_stream_item(nghttp2_session *session,
+                                      nghttp2_stream *stream,
+                                      nghttp2_outbound_item *item) {
+  int rv;
+
+  rv = nghttp2_stream_attach_item(stream, item);
+  if (rv != 0) {
+    return rv;
+  }
+
+  if (!(stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES)) {
+    return 0;
+  }
+
+  return session_ob_data_push(session, stream);
+}
+
+static int session_detach_stream_item(nghttp2_session *session,
+                                      nghttp2_stream *stream) {
+  int rv;
+
+  rv = nghttp2_stream_detach_item(stream);
+  if (rv != 0) {
+    return rv;
+  }
+
+  if (!(stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) ||
+      !stream->queued) {
+    return 0;
+  }
+
+  return session_ob_data_remove(session, stream);
+}
+
+static int session_defer_stream_item(nghttp2_session *session,
+                                     nghttp2_stream *stream, uint8_t flags) {
+  int rv;
+
+  rv = nghttp2_stream_defer_item(stream, flags);
+  if (rv != 0) {
+    return rv;
+  }
+
+  if (!(stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) ||
+      !stream->queued) {
+    return 0;
+  }
+
+  return session_ob_data_remove(session, stream);
+}
+
+static int session_resume_deferred_stream_item(nghttp2_session *session,
+                                               nghttp2_stream *stream,
+                                               uint8_t flags) {
+  int rv;
+
+  rv = nghttp2_stream_resume_deferred_item(stream, flags);
+  if (rv != 0) {
+    return rv;
+  }
+
+  if (!(stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) ||
+      (stream->flags & NGHTTP2_STREAM_FLAG_DEFERRED_ALL)) {
+    return 0;
+  }
+
+  return session_ob_data_push(session, stream);
+}
+
+static nghttp2_outbound_item *
+session_sched_get_next_outbound_item(nghttp2_session *session) {
+  size_t i;
+  nghttp2_pq_entry *ent;
+  nghttp2_stream *stream;
+
+  for (i = 0; i < NGHTTP2_EXTPRI_URGENCY_LEVELS; ++i) {
+    ent = nghttp2_pq_top(&session->sched[i].ob_data);
+    if (!ent) {
+      continue;
+    }
+
+    stream = nghttp2_struct_of(ent, nghttp2_stream, pq_entry);
+    return stream->item;
+  }
+
+  return NULL;
+}
+
+static int session_sched_empty(nghttp2_session *session) {
+  size_t i;
+
+  for (i = 0; i < NGHTTP2_EXTPRI_URGENCY_LEVELS; ++i) {
+    if (!nghttp2_pq_empty(&session->sched[i].ob_data)) {
+      return 0;
+    }
+  }
+
+  return 1;
+}
+
+static void session_sched_reschedule_stream(nghttp2_session *session,
+                                            nghttp2_stream *stream) {
+  nghttp2_pq *pq;
+  uint32_t urgency = nghttp2_extpri_uint8_urgency(stream->extpri);
+  int inc = nghttp2_extpri_uint8_inc(stream->extpri);
+  uint64_t penalty = (uint64_t)stream->last_writelen;
+  int rv;
+
+  (void)rv;
+
+  assert(urgency < NGHTTP2_EXTPRI_URGENCY_LEVELS);
+
+  pq = &session->sched[urgency].ob_data;
+
+  if (!inc || nghttp2_pq_size(pq) == 1) {
+    return;
+  }
+
+  nghttp2_pq_remove(pq, &stream->pq_entry);
+
+  stream->cycle += penalty;
+
+  rv = nghttp2_pq_push(pq, &stream->pq_entry);
+
+  assert(0 == rv);
+}
+
+static int session_update_stream_priority(nghttp2_session *session,
+                                          nghttp2_stream *stream,
+                                          uint8_t u8extpri) {
+  if (stream->extpri == u8extpri) {
+    return 0;
+  }
+
+  if (stream->queued) {
+    session_ob_data_remove(session, stream);
+
+    stream->extpri = u8extpri;
+
+    return session_ob_data_push(session, stream);
+  }
+
+  stream->extpri = u8extpri;
+
+  return 0;
+}
+
 int nghttp2_session_add_item(nghttp2_session *session,
                              nghttp2_outbound_item *item) {
   /* TODO Return error if stream is not found for the frame requiring
@@ -857,7 +1127,7 @@ int nghttp2_session_add_item(nghttp2_session *session,
       return NGHTTP2_ERR_DATA_EXIST;
     }
 
-    rv = nghttp2_stream_attach_item(stream, item);
+    rv = session_attach_stream_item(session, stream, item);
 
     if (rv != 0) {
       return rv;
@@ -953,6 +1223,18 @@ int nghttp2_session_add_rst_stream(nghttp2_session *session, int32_t stream_id,
     return 0;
   }
 
+  /* Sending RST_STREAM to an idle stream is subject to protocol
+     violation.  Historically, nghttp2 allows this.  In order not to
+     disrupt the existing applications, we don't error out this case
+     and simply ignore it. */
+  if (nghttp2_session_is_my_stream_id(session, stream_id)) {
+    if ((uint32_t)stream_id >= session->next_stream_id) {
+      return 0;
+    }
+  } else if (session->last_recv_stream_id < stream_id) {
+    return 0;
+  }
+
   /* Cancel pending request HEADERS in ob_syn if this RST_STREAM
      refers to that stream. */
   if (!session->server && nghttp2_session_is_my_stream_id(session, stream_id) &&
@@ -963,8 +1245,7 @@ int nghttp2_session_add_rst_stream(nghttp2_session *session, int32_t stream_id,
     headers_frame = &nghttp2_outbound_queue_top(&session->ob_syn)->frame;
     assert(headers_frame->hd.type == NGHTTP2_HEADERS);
 
-    if (headers_frame->hd.stream_id <= stream_id &&
-        (uint32_t)stream_id < session->next_stream_id) {
+    if (headers_frame->hd.stream_id <= stream_id) {
 
       for (item = session->ob_syn.head; item; item = item->qnext) {
         aux_data = &item->aux_data.headers;
@@ -1022,13 +1303,27 @@ nghttp2_stream *nghttp2_session_open_stream(nghttp2_session *session,
   mem = &session->mem;
   stream = nghttp2_session_get_stream_raw(session, stream_id);
 
+  if (session->opt_flags &
+      NGHTTP2_OPTMASK_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION) {
+    flags |= NGHTTP2_STREAM_FLAG_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION;
+  }
+
   if (stream) {
     assert(stream->state == NGHTTP2_STREAM_IDLE);
-    assert(nghttp2_stream_in_dep_tree(stream));
-    nghttp2_session_detach_idle_stream(session, stream);
-    rv = nghttp2_stream_dep_remove(stream);
-    if (rv != 0) {
-      return NULL;
+    assert((stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) ||
+           nghttp2_stream_in_dep_tree(stream));
+
+    if (nghttp2_stream_in_dep_tree(stream)) {
+      assert(!(stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES));
+      nghttp2_session_detach_idle_stream(session, stream);
+      rv = nghttp2_stream_dep_remove(stream);
+      if (rv != 0) {
+        return NULL;
+      }
+
+      if (session_no_rfc7540_pri_no_fallback(session)) {
+        stream->flags |= NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES;
+      }
     }
   } else {
     stream = nghttp2_mem_malloc(mem, sizeof(nghttp2_stream));
@@ -1039,7 +1334,21 @@ nghttp2_stream *nghttp2_session_open_stream(nghttp2_session *session,
     stream_alloc = 1;
   }
 
-  if (pri_spec->stream_id != 0) {
+  if (session_no_rfc7540_pri_no_fallback(session) ||
+      session->remote_settings.no_rfc7540_priorities == 1) {
+    /* For client which has not received server
+       SETTINGS_NO_RFC7540_PRIORITIES = 1, send a priority signal
+       opportunistically. */
+    if (session->server ||
+        session->remote_settings.no_rfc7540_priorities == 1) {
+      nghttp2_priority_spec_default_init(&pri_spec_default);
+      pri_spec = &pri_spec_default;
+    }
+
+    if (session->pending_no_rfc7540_priorities == 1) {
+      flags |= NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES;
+    }
+  } else if (pri_spec->stream_id != 0) {
     dep_stream = nghttp2_session_get_stream_raw(session, pri_spec->stream_id);
 
     if (!dep_stream &&
@@ -1085,7 +1394,11 @@ nghttp2_stream *nghttp2_session_open_stream(nghttp2_session *session,
                         (int32_t)session->local_settings.initial_window_size,
                         stream_user_data, mem);
 
-    rv = nghttp2_map_insert(&session->streams, &stream->map_entry);
+    if (session_no_rfc7540_pri_no_fallback(session)) {
+      stream->seq = session->stream_seq++;
+    }
+
+    rv = nghttp2_map_insert(&session->streams, stream_id, stream);
     if (rv != 0) {
       nghttp2_stream_free(stream);
       nghttp2_mem_free(mem, stream);
@@ -1124,6 +1437,10 @@ nghttp2_stream *nghttp2_session_open_stream(nghttp2_session *session,
     }
   }
 
+  if (stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) {
+    return stream;
+  }
+
   if (pri_spec->stream_id == 0) {
     dep_stream = &session->root;
   }
@@ -1163,7 +1480,7 @@ int nghttp2_session_close_stream(nghttp2_session *session, int32_t stream_id,
 
     item = stream->item;
 
-    rv = nghttp2_stream_detach_item(stream);
+    rv = session_detach_stream_item(session, stream);
 
     if (rv != 0) {
       return rv;
@@ -1213,6 +1530,10 @@ int nghttp2_session_close_stream(nghttp2_session *session, int32_t stream_id,
   /* Closes both directions just in case they are not closed yet */
   stream->flags |= NGHTTP2_STREAM_FLAG_CLOSED;
 
+  if (session->pending_no_rfc7540_priorities == 1) {
+    return nghttp2_session_destroy_stream(session, stream);
+  }
+
   if ((session->opt_flags & NGHTTP2_OPTMASK_NO_CLOSED_STREAMS) == 0 &&
       session->server && !is_my_stream_id &&
       nghttp2_stream_in_dep_tree(stream)) {
@@ -1767,6 +2088,28 @@ static int session_predicate_origin_send(nghttp2_session *session) {
   return 0;
 }
 
+static int session_predicate_priority_update_send(nghttp2_session *session,
+                                                  int32_t stream_id) {
+  nghttp2_stream *stream;
+
+  if (session_is_closing(session)) {
+    return NGHTTP2_ERR_SESSION_CLOSING;
+  }
+
+  stream = nghttp2_session_get_stream(session, stream_id);
+  if (stream == NULL) {
+    return 0;
+  }
+  if (stream->state == NGHTTP2_STREAM_CLOSING) {
+    return NGHTTP2_ERR_STREAM_CLOSING;
+  }
+  if (stream->shut_flags & NGHTTP2_SHUT_RD) {
+    return NGHTTP2_ERR_INVALID_STREAM_STATE;
+  }
+
+  return 0;
+}
+
 /* Take into account settings max frame size and both connection-level
    flow control here */
 static ssize_t
@@ -1996,7 +2339,7 @@ static int session_prep_frame(nghttp2_session *session,
       if (stream) {
         int rv2;
 
-        rv2 = nghttp2_stream_detach_item(stream);
+        rv2 = session_detach_stream_item(session, stream);
 
         if (nghttp2_is_fatal(rv2)) {
           return rv2;
@@ -2015,7 +2358,7 @@ static int session_prep_frame(nghttp2_session *session,
          queue when session->remote_window_size > 0 */
       assert(session->remote_window_size > 0);
 
-      rv = nghttp2_stream_defer_item(stream,
+      rv = session_defer_stream_item(session, stream,
                                      NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL);
 
       if (nghttp2_is_fatal(rv)) {
@@ -2034,7 +2377,8 @@ static int session_prep_frame(nghttp2_session *session,
       return rv;
     }
     if (rv == NGHTTP2_ERR_DEFERRED) {
-      rv = nghttp2_stream_defer_item(stream, NGHTTP2_STREAM_FLAG_DEFERRED_USER);
+      rv = session_defer_stream_item(session, stream,
+                                     NGHTTP2_STREAM_FLAG_DEFERRED_USER);
 
       if (nghttp2_is_fatal(rv)) {
         return rv;
@@ -2045,7 +2389,7 @@ static int session_prep_frame(nghttp2_session *session,
       return NGHTTP2_ERR_DEFERRED;
     }
     if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
-      rv = nghttp2_stream_detach_item(stream);
+      rv = session_detach_stream_item(session, stream);
 
       if (nghttp2_is_fatal(rv)) {
         return rv;
@@ -2061,7 +2405,7 @@ static int session_prep_frame(nghttp2_session *session,
     if (rv != 0) {
       int rv2;
 
-      rv2 = nghttp2_stream_detach_item(stream);
+      rv2 = session_detach_stream_item(session, stream);
 
       if (nghttp2_is_fatal(rv2)) {
         return rv2;
@@ -2311,6 +2655,18 @@ static int session_prep_frame(nghttp2_session *session,
       }
 
       return 0;
+    case NGHTTP2_PRIORITY_UPDATE: {
+      nghttp2_ext_priority_update *priority_update = frame->ext.payload;
+      rv = session_predicate_priority_update_send(session,
+                                                  priority_update->stream_id);
+      if (rv != 0) {
+        return rv;
+      }
+
+      nghttp2_frame_pack_priority_update(&session->aob.framebufs, &frame->ext);
+
+      return 0;
+    }
     default:
       /* Unreachable here */
       assert(0);
@@ -2322,6 +2678,8 @@ static int session_prep_frame(nghttp2_session *session,
 
 nghttp2_outbound_item *
 nghttp2_session_get_next_ob_item(nghttp2_session *session) {
+  nghttp2_outbound_item *item;
+
   if (nghttp2_outbound_queue_top(&session->ob_urgent)) {
     return nghttp2_outbound_queue_top(&session->ob_urgent);
   }
@@ -2337,7 +2695,12 @@ nghttp2_session_get_next_ob_item(nghttp2_session *session) {
   }
 
   if (session->remote_window_size > 0) {
-    return nghttp2_stream_next_outbound_item(&session->root);
+    item = nghttp2_stream_next_outbound_item(&session->root);
+    if (item) {
+      return item;
+    }
+
+    return session_sched_get_next_outbound_item(session);
   }
 
   return NULL;
@@ -2371,7 +2734,12 @@ nghttp2_session_pop_next_ob_item(nghttp2_session *session) {
   }
 
   if (session->remote_window_size > 0) {
-    return nghttp2_stream_next_outbound_item(&session->root);
+    item = nghttp2_stream_next_outbound_item(&session->root);
+    if (item) {
+      return item;
+    }
+
+    return session_sched_get_next_outbound_item(session);
   }
 
   return NULL;
@@ -2407,7 +2775,7 @@ static int session_call_on_frame_send(nghttp2_session *session,
   return 0;
 }
 
-static int find_stream_on_goaway_func(nghttp2_map_entry *entry, void *ptr) {
+static int find_stream_on_goaway_func(void *entry, void *ptr) {
   nghttp2_close_stream_on_goaway_arg *arg;
   nghttp2_stream *stream;
 
@@ -2481,10 +2849,20 @@ static int session_close_stream_on_goaway(nghttp2_session *session,
   return 0;
 }
 
-static void reschedule_stream(nghttp2_stream *stream) {
+static void session_reschedule_stream(nghttp2_session *session,
+                                      nghttp2_stream *stream) {
   stream->last_writelen = stream->item->frame.hd.length;
 
-  nghttp2_stream_reschedule(stream);
+  if (!(stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES)) {
+    nghttp2_stream_reschedule(stream);
+    return;
+  }
+
+  if (!session->server) {
+    return;
+  }
+
+  session_sched_reschedule_stream(session, stream);
 }
 
 static int session_update_stream_consumed_size(nghttp2_session *session,
@@ -2494,14 +2872,6 @@ static int session_update_stream_consumed_size(nghttp2_session *session,
 static int session_update_connection_consumed_size(nghttp2_session *session,
                                                    size_t delta_size);
 
-static int session_update_recv_connection_window_size(nghttp2_session *session,
-                                                      size_t delta_size);
-
-static int session_update_recv_stream_window_size(nghttp2_session *session,
-                                                  nghttp2_stream *stream,
-                                                  size_t delta_size,
-                                                  int send_window_update);
-
 /*
  * Called after a frame is sent.  This function runs
  * on_frame_send_callback and handles stream closure upon END_STREAM
@@ -2541,7 +2911,7 @@ static int session_after_frame_sent1(nghttp2_session *session) {
     }
 
     if (stream && aux_data->eof) {
-      rv = nghttp2_stream_detach_item(stream);
+      rv = session_detach_stream_item(session, stream);
       if (nghttp2_is_fatal(rv)) {
         return rv;
       }
@@ -2666,9 +3036,8 @@ static int session_after_frame_sent1(nghttp2_session *session) {
     }
   }
   case NGHTTP2_PRIORITY:
-    if (session->server) {
+    if (session->server || session->pending_no_rfc7540_priorities == 1) {
       return 0;
-      ;
     }
 
     stream = nghttp2_session_get_stream_raw(session, frame->hd.stream_id);
@@ -2735,7 +3104,7 @@ static int session_after_frame_sent1(nghttp2_session *session) {
       if (session->opt_flags & NGHTTP2_OPTMASK_NO_AUTO_WINDOW_UPDATE) {
         rv = session_update_connection_consumed_size(session, 0);
       } else {
-        rv = session_update_recv_connection_window_size(session, 0);
+        rv = nghttp2_session_update_recv_connection_window_size(session, 0);
       }
 
       if (nghttp2_is_fatal(rv)) {
@@ -2761,7 +3130,8 @@ static int session_after_frame_sent1(nghttp2_session *session) {
     if (session->opt_flags & NGHTTP2_OPTMASK_NO_AUTO_WINDOW_UPDATE) {
       rv = session_update_stream_consumed_size(session, stream, 0);
     } else {
-      rv = session_update_recv_stream_window_size(session, stream, 0, 1);
+      rv =
+          nghttp2_session_update_recv_stream_window_size(session, stream, 0, 1);
     }
 
     if (nghttp2_is_fatal(rv)) {
@@ -2842,7 +3212,7 @@ static int session_after_frame_sent2(nghttp2_session *session) {
      further data. */
   if (nghttp2_session_predicate_data_send(session, stream) != 0) {
     if (stream) {
-      rv = nghttp2_stream_detach_item(stream);
+      rv = session_detach_stream_item(session, stream);
 
       if (nghttp2_is_fatal(rv)) {
         return rv;
@@ -3140,7 +3510,7 @@ static ssize_t nghttp2_session_mem_send_internal(nghttp2_session *session,
       }
 
       if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
-        rv = nghttp2_stream_detach_item(stream);
+        rv = session_detach_stream_item(session, stream);
 
         if (nghttp2_is_fatal(rv)) {
           return rv;
@@ -3720,6 +4090,21 @@ static int session_end_stream_headers_received(nghttp2_session *session,
                                                nghttp2_frame *frame,
                                                nghttp2_stream *stream) {
   int rv;
+
+  assert(frame->hd.type == NGHTTP2_HEADERS);
+
+  if (session->server && session_enforce_http_messaging(session) &&
+      frame->headers.cat == NGHTTP2_HCAT_REQUEST &&
+      (stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) &&
+      !(stream->flags & NGHTTP2_STREAM_FLAG_IGNORE_CLIENT_PRIORITIES) &&
+      (stream->http_flags & NGHTTP2_HTTP_FLAG_PRIORITY)) {
+    rv = session_update_stream_priority(session, stream, stream->http_extpri);
+    if (rv != 0) {
+      assert(nghttp2_is_fatal(rv));
+      return rv;
+    }
+  }
+
   if ((frame->hd.flags & NGHTTP2_FLAG_END_STREAM) == 0) {
     return 0;
   }
@@ -4081,6 +4466,8 @@ int nghttp2_session_on_priority_received(nghttp2_session *session,
   int rv;
   nghttp2_stream *stream;
 
+  assert(!session_no_rfc7540_pri_no_fallback(session));
+
   if (frame->hd.stream_id == 0) {
     return session_handle_invalid_connection(session, frame, NGHTTP2_ERR_PROTO,
                                              "PRIORITY: stream_id == 0");
@@ -4138,6 +4525,8 @@ static int session_process_priority_frame(nghttp2_session *session) {
   nghttp2_inbound_frame *iframe = &session->iframe;
   nghttp2_frame *frame = &iframe->frame;
 
+  assert(!session_no_rfc7540_pri_no_fallback(session));
+
   nghttp2_frame_unpack_priority_payload(&frame->priority, iframe->sbuf.pos);
 
   return nghttp2_session_on_priority_received(session, frame);
@@ -4184,8 +4573,7 @@ static int session_process_rst_stream_frame(nghttp2_session *session) {
   return nghttp2_session_on_rst_stream_received(session, frame);
 }
 
-static int update_remote_initial_window_size_func(nghttp2_map_entry *entry,
-                                                  void *ptr) {
+static int update_remote_initial_window_size_func(void *entry, void *ptr) {
   int rv;
   nghttp2_update_window_size_arg *arg;
   nghttp2_stream *stream;
@@ -4205,8 +4593,8 @@ static int update_remote_initial_window_size_func(nghttp2_map_entry *entry,
   if (stream->remote_window_size > 0 &&
       nghttp2_stream_check_deferred_by_flow_control(stream)) {
 
-    rv = nghttp2_stream_resume_deferred_item(
-        stream, NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL);
+    rv = session_resume_deferred_stream_item(
+        arg->session, stream, NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL);
 
     if (nghttp2_is_fatal(rv)) {
       return rv;
@@ -4238,8 +4626,7 @@ session_update_remote_initial_window_size(nghttp2_session *session,
                           update_remote_initial_window_size_func, &arg);
 }
 
-static int update_local_initial_window_size_func(nghttp2_map_entry *entry,
-                                                 void *ptr) {
+static int update_local_initial_window_size_func(void *entry, void *ptr) {
   int rv;
   nghttp2_update_window_size_arg *arg;
   nghttp2_stream *stream;
@@ -4251,9 +4638,16 @@ static int update_local_initial_window_size_func(nghttp2_map_entry *entry,
     return nghttp2_session_add_rst_stream(arg->session, stream->stream_id,
                                           NGHTTP2_FLOW_CONTROL_ERROR);
   }
-  if (!(arg->session->opt_flags & NGHTTP2_OPTMASK_NO_AUTO_WINDOW_UPDATE) &&
-      stream->window_update_queued == 0 &&
-      nghttp2_should_send_window_update(stream->local_window_size,
+
+  if (stream->window_update_queued) {
+    return 0;
+  }
+
+  if (arg->session->opt_flags & NGHTTP2_OPTMASK_NO_AUTO_WINDOW_UPDATE) {
+    return session_update_stream_consumed_size(arg->session, stream, 0);
+  }
+
+  if (nghttp2_should_send_window_update(stream->local_window_size,
                                         stream->recv_window_size)) {
 
     rv = nghttp2_session_add_window_update(arg->session, NGHTTP2_FLAG_NONE,
@@ -4374,6 +4768,9 @@ int nghttp2_session_update_local_settings(nghttp2_session *session,
     case NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL:
       session->local_settings.enable_connect_protocol = iv[i].value;
       break;
+    case NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES:
+      session->local_settings.no_rfc7540_priorities = iv[i].value;
+      break;
     }
   }
 
@@ -4533,6 +4930,34 @@ int nghttp2_session_on_settings_received(nghttp2_session *session,
       session->remote_settings.enable_connect_protocol = entry->value;
 
       break;
+    case NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES:
+
+      if (entry->value != 0 && entry->value != 1) {
+        return session_handle_invalid_connection(
+            session, frame, NGHTTP2_ERR_PROTO,
+            "SETTINGS: invalid SETTINGS_NO_RFC7540_PRIORITIES");
+      }
+
+      if (session->remote_settings.no_rfc7540_priorities != UINT32_MAX &&
+          session->remote_settings.no_rfc7540_priorities != entry->value) {
+        return session_handle_invalid_connection(
+            session, frame, NGHTTP2_ERR_PROTO,
+            "SETTINGS: SETTINGS_NO_RFC7540_PRIORITIES cannot be changed");
+      }
+
+      session->remote_settings.no_rfc7540_priorities = entry->value;
+
+      break;
+    }
+  }
+
+  if (session->remote_settings.no_rfc7540_priorities == UINT32_MAX) {
+    session->remote_settings.no_rfc7540_priorities = 0;
+
+    if (session->server && session->pending_no_rfc7540_priorities &&
+        (session->opt_flags &
+         NGHTTP2_OPTMASK_SERVER_FALLBACK_RFC7540_PRIORITIES)) {
+      session->fallback_rfc7540_priorities = 1;
     }
   }
 
@@ -4818,8 +5243,8 @@ static int session_on_stream_window_update_received(nghttp2_session *session,
   if (stream->remote_window_size > 0 &&
       nghttp2_stream_check_deferred_by_flow_control(stream)) {
 
-    rv = nghttp2_stream_resume_deferred_item(
-        stream, NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL);
+    rv = session_resume_deferred_stream_item(
+        session, stream, NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL);
 
     if (nghttp2_is_fatal(rv)) {
       return rv;
@@ -4890,6 +5315,80 @@ int nghttp2_session_on_origin_received(nghttp2_session *session,
   return session_call_on_frame_received(session, frame);
 }
 
+int nghttp2_session_on_priority_update_received(nghttp2_session *session,
+                                                nghttp2_frame *frame) {
+  nghttp2_ext_priority_update *priority_update;
+  nghttp2_stream *stream;
+  nghttp2_priority_spec pri_spec;
+  nghttp2_extpri extpri;
+  int rv;
+
+  assert(session->server);
+
+  priority_update = frame->ext.payload;
+
+  if (frame->hd.stream_id != 0) {
+    return session_handle_invalid_connection(session, frame, NGHTTP2_ERR_PROTO,
+                                             "PRIORITY_UPDATE: stream_id == 0");
+  }
+
+  if (nghttp2_session_is_my_stream_id(session, priority_update->stream_id)) {
+    if (session_detect_idle_stream(session, priority_update->stream_id)) {
+      return session_handle_invalid_connection(
+          session, frame, NGHTTP2_ERR_PROTO,
+          "PRIORITY_UPDATE: prioritizing idle push is not allowed");
+    }
+
+    /* TODO Ignore priority signal to a push stream for now */
+    return session_call_on_frame_received(session, frame);
+  }
+
+  stream = nghttp2_session_get_stream_raw(session, priority_update->stream_id);
+  if (stream) {
+    /* Stream already exists. */
+    if (stream->flags & NGHTTP2_STREAM_FLAG_IGNORE_CLIENT_PRIORITIES) {
+      return session_call_on_frame_received(session, frame);
+    }
+  } else if (session_detect_idle_stream(session, priority_update->stream_id)) {
+    if (session->num_idle_streams + session->num_incoming_streams >=
+        session->local_settings.max_concurrent_streams) {
+      return session_handle_invalid_connection(
+          session, frame, NGHTTP2_ERR_PROTO,
+          "PRIORITY_UPDATE: max concurrent streams exceeded");
+    }
+
+    nghttp2_priority_spec_default_init(&pri_spec);
+    stream = nghttp2_session_open_stream(session, priority_update->stream_id,
+                                         NGHTTP2_FLAG_NONE, &pri_spec,
+                                         NGHTTP2_STREAM_IDLE, NULL);
+    if (!stream) {
+      return NGHTTP2_ERR_NOMEM;
+    }
+  } else {
+    return session_call_on_frame_received(session, frame);
+  }
+
+  extpri.urgency = NGHTTP2_EXTPRI_DEFAULT_URGENCY;
+  extpri.inc = 0;
+
+  rv = nghttp2_http_parse_priority(&extpri, priority_update->field_value,
+                                   priority_update->field_value_len);
+  if (rv != 0) {
+    /* Just ignore field_value if it cannot be parsed. */
+    return session_call_on_frame_received(session, frame);
+  }
+
+  rv = session_update_stream_priority(session, stream,
+                                      nghttp2_extpri_to_uint8(&extpri));
+  if (rv != 0) {
+    if (nghttp2_is_fatal(rv)) {
+      return rv;
+    }
+  }
+
+  return session_call_on_frame_received(session, frame);
+}
+
 static int session_process_altsvc_frame(nghttp2_session *session) {
   nghttp2_inbound_frame *iframe = &session->iframe;
   nghttp2_frame *frame = &iframe->frame;
@@ -4924,6 +5423,16 @@ static int session_process_origin_frame(nghttp2_session *session) {
   return nghttp2_session_on_origin_received(session, frame);
 }
 
+static int session_process_priority_update_frame(nghttp2_session *session) {
+  nghttp2_inbound_frame *iframe = &session->iframe;
+  nghttp2_frame *frame = &iframe->frame;
+
+  nghttp2_frame_unpack_priority_update_payload(&frame->ext, iframe->sbuf.pos,
+                                               nghttp2_buf_len(&iframe->sbuf));
+
+  return nghttp2_session_on_priority_update_received(session, frame);
+}
+
 static int session_process_extension_frame(nghttp2_session *session) {
   int rv;
   nghttp2_inbound_frame *iframe = &session->iframe;
@@ -5019,22 +5528,10 @@ static int adjust_recv_window_size(int32_t *recv_window_size_ptr, size_t delta,
   return 0;
 }
 
-/*
- * Accumulates received bytes |delta_size| for stream-level flow
- * control and decides whether to send WINDOW_UPDATE to that stream.
- * If NGHTTP2_OPT_NO_AUTO_WINDOW_UPDATE is set, WINDOW_UPDATE will not
- * be sent.
- *
- * This function returns 0 if it succeeds, or one of the following
- * negative error codes:
- *
- * NGHTTP2_ERR_NOMEM
- *     Out of memory.
- */
-static int session_update_recv_stream_window_size(nghttp2_session *session,
-                                                  nghttp2_stream *stream,
-                                                  size_t delta_size,
-                                                  int send_window_update) {
+int nghttp2_session_update_recv_stream_window_size(nghttp2_session *session,
+                                                   nghttp2_stream *stream,
+                                                   size_t delta_size,
+                                                   int send_window_update) {
   int rv;
   rv = adjust_recv_window_size(&stream->recv_window_size, delta_size,
                                stream->local_window_size);
@@ -5063,20 +5560,8 @@ static int session_update_recv_stream_window_size(nghttp2_session *session,
   return 0;
 }
 
-/*
- * Accumulates received bytes |delta_size| for connection-level flow
- * control and decides whether to send WINDOW_UPDATE to the
- * connection.  If NGHTTP2_OPT_NO_AUTO_WINDOW_UPDATE is set,
- * WINDOW_UPDATE will not be sent.
- *
- * This function returns 0 if it succeeds, or one of the following
- * negative error codes:
- *
- * NGHTTP2_ERR_NOMEM
- *     Out of memory.
- */
-static int session_update_recv_connection_window_size(nghttp2_session *session,
-                                                      size_t delta_size) {
+int nghttp2_session_update_recv_connection_window_size(nghttp2_session *session,
+                                                       size_t delta_size) {
   int rv;
   rv = adjust_recv_window_size(&session->recv_window_size, delta_size,
                                session->local_window_size);
@@ -5285,6 +5770,7 @@ static void inbound_frame_set_settings_entry(nghttp2_inbound_frame *iframe) {
   case NGHTTP2_SETTINGS_MAX_FRAME_SIZE:
   case NGHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE:
   case NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL:
+  case NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES:
     break;
   default:
     DEBUGF("recv: unknown settings id=0x%02x\n", iv.settings_id);
@@ -5357,7 +5843,7 @@ static ssize_t inbound_frame_compute_pad(nghttp2_inbound_frame *iframe) {
 
 /*
  * This function returns the effective payload length in the data of
- * length |readlen| when the remaning payload is |payloadleft|. The
+ * length |readlen| when the remaining payload is |payloadleft|. The
  * |payloadleft| does not include |readlen|. If padding was started
  * strictly before this data chunk, this function returns -1.
  */
@@ -5378,9 +5864,11 @@ static ssize_t inbound_frame_effective_readlen(nghttp2_inbound_frame *iframe,
   return (ssize_t)(readlen);
 }
 
+static const uint8_t static_in[] = {0};
+
 ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
                                  size_t inlen) {
-  const uint8_t *first = in, *last = in + inlen;
+  const uint8_t *first, *last;
   nghttp2_inbound_frame *iframe = &session->iframe;
   size_t readlen;
   ssize_t padlen;
@@ -5391,6 +5879,14 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
   size_t pri_fieldlen;
   nghttp2_mem *mem;
 
+  if (in == NULL) {
+    assert(inlen == 0);
+    in = static_in;
+  }
+
+  first = in;
+  last = in + inlen;
+
   DEBUGF("recv: connection recv_window_size=%d, local_window=%d\n",
          session->recv_window_size, session->local_window_size);
 
@@ -5678,6 +6174,12 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           break;
         }
 
+        /* Check the settings flood counter early to be safe */
+        if (session->obq_flood_counter_ >= session->max_outbound_ack &&
+            !(iframe->frame.hd.flags & NGHTTP2_FLAG_ACK)) {
+          return NGHTTP2_ERR_FLOODED;
+        }
+
         iframe->state = NGHTTP2_IB_READ_SETTINGS;
 
         if (iframe->payloadleft) {
@@ -5688,6 +6190,16 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           iframe->max_niv =
               iframe->frame.hd.length / NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH + 1;
 
+          if (iframe->max_niv - 1 > session->max_settings) {
+            rv = nghttp2_session_terminate_session_with_reason(
+                session, NGHTTP2_ENHANCE_YOUR_CALM,
+                "SETTINGS: too many setting entries");
+            if (nghttp2_is_fatal(rv)) {
+              return rv;
+            }
+            return (ssize_t)inlen;
+          }
+
           iframe->iv = nghttp2_mem_malloc(mem, sizeof(nghttp2_settings_entry) *
                                                    iframe->max_niv);
 
@@ -5873,6 +6385,49 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
             iframe->state = NGHTTP2_IB_READ_ORIGIN_PAYLOAD;
 
             break;
+          case NGHTTP2_PRIORITY_UPDATE:
+            if ((session->builtin_recv_ext_types &
+                 NGHTTP2_TYPEMASK_PRIORITY_UPDATE) == 0) {
+              busy = 1;
+              iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+              break;
+            }
+
+            DEBUGF("recv: PRIORITY_UPDATE\n");
+
+            iframe->frame.hd.flags = NGHTTP2_FLAG_NONE;
+            iframe->frame.ext.payload =
+                &iframe->ext_frame_payload.priority_update;
+
+            if (!session->server) {
+              rv = nghttp2_session_terminate_session_with_reason(
+                  session, NGHTTP2_PROTOCOL_ERROR,
+                  "PRIORITY_UPDATE is received from server");
+              if (nghttp2_is_fatal(rv)) {
+                return rv;
+              }
+              return (ssize_t)inlen;
+            }
+
+            if (iframe->payloadleft < 4) {
+              busy = 1;
+              iframe->state = NGHTTP2_IB_FRAME_SIZE_ERROR;
+              break;
+            }
+
+            if (!session_no_rfc7540_pri_no_fallback(session) ||
+                iframe->payloadleft > sizeof(iframe->raw_sbuf)) {
+              busy = 1;
+              iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+              break;
+            }
+
+            busy = 1;
+
+            iframe->state = NGHTTP2_IB_READ_NBYTE;
+            inbound_frame_set_mark(iframe, iframe->payloadleft);
+
+            break;
           default:
             busy = 1;
 
@@ -5978,13 +6533,16 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
         break;
       case NGHTTP2_PRIORITY:
-        rv = session_process_priority_frame(session);
-        if (nghttp2_is_fatal(rv)) {
-          return rv;
-        }
+        if (!session_no_rfc7540_pri_no_fallback(session) &&
+            session->remote_settings.no_rfc7540_priorities != 1) {
+          rv = session_process_priority_frame(session);
+          if (nghttp2_is_fatal(rv)) {
+            return rv;
+          }
 
-        if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          if (iframe->state == NGHTTP2_IB_IGN_ALL) {
+            return (ssize_t)inlen;
+          }
         }
 
         session_inbound_frame_reset(session);
@@ -6141,6 +6699,18 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         iframe->state = NGHTTP2_IB_READ_ALTSVC_PAYLOAD;
 
         break;
+      case NGHTTP2_PRIORITY_UPDATE:
+        DEBUGF("recv: prioritized_stream_id=%d\n",
+               nghttp2_get_uint32(iframe->sbuf.pos) & NGHTTP2_STREAM_ID_MASK);
+
+        rv = session_process_priority_update_frame(session);
+        if (nghttp2_is_fatal(rv)) {
+          return rv;
+        }
+
+        session_inbound_frame_reset(session);
+
+        break;
       }
       default:
         /* This is unknown frame */
@@ -6420,8 +6990,9 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
       /* CONTINUATION won't bear NGHTTP2_PADDED flag */
 
-      iframe->frame.hd.flags = (uint8_t)(
-          iframe->frame.hd.flags | (cont_hd.flags & NGHTTP2_FLAG_END_HEADERS));
+      iframe->frame.hd.flags =
+          (uint8_t)(iframe->frame.hd.flags |
+                    (cont_hd.flags & NGHTTP2_FLAG_END_HEADERS));
       iframe->frame.hd.length += cont_hd.length;
 
       busy = 1;
@@ -6454,7 +7025,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       }
 
       /* Pad Length field is subject to flow control */
-      rv = session_update_recv_connection_window_size(session, readlen);
+      rv = nghttp2_session_update_recv_connection_window_size(session, readlen);
       if (nghttp2_is_fatal(rv)) {
         return rv;
       }
@@ -6477,7 +7048,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
       stream = nghttp2_session_get_stream(session, iframe->frame.hd.stream_id);
       if (stream) {
-        rv = session_update_recv_stream_window_size(
+        rv = nghttp2_session_update_recv_stream_window_size(
             session, stream, readlen,
             iframe->payloadleft ||
                 (iframe->frame.hd.flags & NGHTTP2_FLAG_END_STREAM) == 0);
@@ -6524,7 +7095,8 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       if (readlen > 0) {
         ssize_t data_readlen;
 
-        rv = session_update_recv_connection_window_size(session, readlen);
+        rv = nghttp2_session_update_recv_connection_window_size(session,
+                                                                readlen);
         if (nghttp2_is_fatal(rv)) {
           return rv;
         }
@@ -6533,7 +7105,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           return (ssize_t)inlen;
         }
 
-        rv = session_update_recv_stream_window_size(
+        rv = nghttp2_session_update_recv_stream_window_size(
             session, stream, readlen,
             iframe->payloadleft ||
                 (iframe->frame.hd.flags & NGHTTP2_FLAG_END_STREAM) == 0);
@@ -6634,7 +7206,8 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       if (readlen > 0) {
         /* Update connection-level flow control window for ignored
            DATA frame too */
-        rv = session_update_recv_connection_window_size(session, readlen);
+        rv = nghttp2_session_update_recv_connection_window_size(session,
+                                                                readlen);
         if (nghttp2_is_fatal(rv)) {
           return rv;
         }
@@ -6850,7 +7423,8 @@ int nghttp2_session_want_write(nghttp2_session *session) {
    */
   return session->aob.item || nghttp2_outbound_queue_top(&session->ob_urgent) ||
          nghttp2_outbound_queue_top(&session->ob_reg) ||
-         (!nghttp2_pq_empty(&session->root.obq) &&
+         ((!nghttp2_pq_empty(&session->root.obq) ||
+           !session_sched_empty(session)) &&
           session->remote_window_size > 0) ||
          (nghttp2_outbound_queue_top(&session->ob_syn) &&
           !session_is_outgoing_concurrent_streams_max(session));
@@ -7003,6 +7577,7 @@ int nghttp2_session_add_settings(nghttp2_session *session, uint8_t flags,
   int rv;
   nghttp2_mem *mem;
   nghttp2_inflight_settings *inflight_settings = NULL;
+  uint8_t no_rfc7540_pri = session->pending_no_rfc7540_priorities;
 
   mem = &session->mem;
 
@@ -7020,6 +7595,21 @@ int nghttp2_session_add_settings(nghttp2_session *session, uint8_t flags,
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
 
+  for (i = 0; i < niv; ++i) {
+    if (iv[i].settings_id != NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES) {
+      continue;
+    }
+
+    if (no_rfc7540_pri == UINT8_MAX) {
+      no_rfc7540_pri = (uint8_t)iv[i].value;
+      continue;
+    }
+
+    if (iv[i].value != (uint32_t)no_rfc7540_pri) {
+      return NGHTTP2_ERR_INVALID_ARGUMENT;
+    }
+  }
+
   item = nghttp2_mem_malloc(mem, sizeof(nghttp2_outbound_item));
   if (item == NULL) {
     return NGHTTP2_ERR_NOMEM;
@@ -7094,6 +7684,12 @@ int nghttp2_session_add_settings(nghttp2_session *session, uint8_t flags,
     }
   }
 
+  if (no_rfc7540_pri == UINT8_MAX) {
+    session->pending_no_rfc7540_priorities = 0;
+  } else {
+    session->pending_no_rfc7540_priorities = no_rfc7540_pri;
+  }
+
   return 0;
 }
 
@@ -7222,7 +7818,7 @@ int nghttp2_session_pack_data(nghttp2_session *session, nghttp2_bufs *bufs,
     return rv;
   }
 
-  reschedule_stream(stream);
+  session_reschedule_stream(session, stream);
 
   if (frame->hd.length == 0 && (data_flags & NGHTTP2_DATA_FLAG_EOF) &&
       (data_flags & NGHTTP2_DATA_FLAG_NO_END_STREAM)) {
@@ -7296,7 +7892,7 @@ int nghttp2_session_resume_data(nghttp2_session *session, int32_t stream_id) {
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
 
-  rv = nghttp2_stream_resume_deferred_item(stream,
+  rv = session_resume_deferred_stream_item(session, stream,
                                            NGHTTP2_STREAM_FLAG_DEFERRED_USER);
 
   if (nghttp2_is_fatal(rv)) {
@@ -7404,6 +8000,8 @@ uint32_t nghttp2_session_get_remote_settings(nghttp2_session *session,
     return session->remote_settings.max_header_list_size;
   case NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL:
     return session->remote_settings.enable_connect_protocol;
+  case NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES:
+    return session->remote_settings.no_rfc7540_priorities;
   }
 
   assert(0);
@@ -7427,6 +8025,8 @@ uint32_t nghttp2_session_get_local_settings(nghttp2_session *session,
     return session->local_settings.max_header_list_size;
   case NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL:
     return session->local_settings.enable_connect_protocol;
+  case NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES:
+    return session->local_settings.no_rfc7540_priorities;
   }
 
   assert(0);
@@ -7454,6 +8054,11 @@ static int nghttp2_session_upgrade_internal(nghttp2_session *session,
   if (settings_payloadlen % NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH) {
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
+  /* SETTINGS frame contains too many settings */
+  if (settings_payloadlen / NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH >
+      session->max_settings) {
+    return NGHTTP2_ERR_TOO_MANY_SETTINGS;
+  }
   rv = nghttp2_frame_unpack_settings_payload2(&iv, &niv, settings_payload,
                                               settings_payloadlen, mem);
   if (rv != 0) {
@@ -7705,6 +8310,10 @@ int nghttp2_session_change_stream_priority(
   nghttp2_stream *stream;
   nghttp2_priority_spec pri_spec_copy;
 
+  if (session->pending_no_rfc7540_priorities == 1) {
+    return 0;
+  }
+
   if (stream_id == 0 || stream_id == pri_spec->stream_id) {
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
@@ -7737,6 +8346,10 @@ int nghttp2_session_create_idle_stream(nghttp2_session *session,
   nghttp2_stream *stream;
   nghttp2_priority_spec pri_spec_copy;
 
+  if (session->pending_no_rfc7540_priorities == 1) {
+    return 0;
+  }
+
   if (stream_id == 0 || stream_id == pri_spec->stream_id ||
       !session_detect_idle_stream(session, stream_id)) {
     return NGHTTP2_ERR_INVALID_ARGUMENT;
@@ -7778,3 +8391,38 @@ nghttp2_session_get_hd_deflate_dynamic_table_size(nghttp2_session *session) {
 void nghttp2_session_set_user_data(nghttp2_session *session, void *user_data) {
   session->user_data = user_data;
 }
+
+int nghttp2_session_change_extpri_stream_priority(
+    nghttp2_session *session, int32_t stream_id,
+    const nghttp2_extpri *extpri_in, int ignore_client_signal) {
+  nghttp2_stream *stream;
+  nghttp2_extpri extpri = *extpri_in;
+
+  if (!session->server) {
+    return NGHTTP2_ERR_INVALID_STATE;
+  }
+
+  if (session->pending_no_rfc7540_priorities != 1) {
+    return 0;
+  }
+
+  if (stream_id == 0) {
+    return NGHTTP2_ERR_INVALID_ARGUMENT;
+  }
+
+  stream = nghttp2_session_get_stream_raw(session, stream_id);
+  if (!stream) {
+    return NGHTTP2_ERR_INVALID_ARGUMENT;
+  }
+
+  if (extpri.urgency > NGHTTP2_EXTPRI_URGENCY_LOW) {
+    extpri.urgency = NGHTTP2_EXTPRI_URGENCY_LOW;
+  }
+
+  if (ignore_client_signal) {
+    stream->flags |= NGHTTP2_STREAM_FLAG_IGNORE_CLIENT_PRIORITIES;
+  }
+
+  return session_update_stream_priority(session, stream,
+                                        nghttp2_extpri_to_uint8(&extpri));
+}
diff --git a/Utilities/cmnghttp2/lib/nghttp2_session.h b/Utilities/cmnghttp2/lib/nghttp2_session.h
index 90ead9c039..34d2d58528 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_session.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_session.h
@@ -52,7 +52,9 @@ typedef enum {
   NGHTTP2_OPTMASK_NO_RECV_CLIENT_MAGIC = 1 << 1,
   NGHTTP2_OPTMASK_NO_HTTP_MESSAGING = 1 << 2,
   NGHTTP2_OPTMASK_NO_AUTO_PING_ACK = 1 << 3,
-  NGHTTP2_OPTMASK_NO_CLOSED_STREAMS = 1 << 4
+  NGHTTP2_OPTMASK_NO_CLOSED_STREAMS = 1 << 4,
+  NGHTTP2_OPTMASK_SERVER_FALLBACK_RFC7540_PRIORITIES = 1 << 5,
+  NGHTTP2_OPTMASK_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION = 1 << 6,
 } nghttp2_optmask;
 
 /*
@@ -62,7 +64,8 @@ typedef enum {
 typedef enum {
   NGHTTP2_TYPEMASK_NONE = 0,
   NGHTTP2_TYPEMASK_ALTSVC = 1 << 0,
-  NGHTTP2_TYPEMASK_ORIGIN = 1 << 1
+  NGHTTP2_TYPEMASK_ORIGIN = 1 << 1,
+  NGHTTP2_TYPEMASK_PRIORITY_UPDATE = 1 << 2
 } nghttp2_typemask;
 
 typedef enum {
@@ -151,10 +154,8 @@ typedef struct {
   /* padding length for the current frame */
   size_t padlen;
   nghttp2_inbound_state state;
-  /* Small buffer.  Currently the largest contiguous chunk to buffer
-     is frame header.  We buffer part of payload, but they are smaller
-     than frame header. */
-  uint8_t raw_sbuf[NGHTTP2_FRAME_HDLEN];
+  /* Small fixed sized buffer. */
+  uint8_t raw_sbuf[32];
 } nghttp2_inbound_frame;
 
 typedef struct {
@@ -165,6 +166,7 @@ typedef struct {
   uint32_t max_frame_size;
   uint32_t max_header_list_size;
   uint32_t enable_connect_protocol;
+  uint32_t no_rfc7540_priorities;
 } nghttp2_settings_storage;
 
 typedef enum {
@@ -202,6 +204,12 @@ struct nghttp2_session {
      response) frame, which are subject to
      SETTINGS_MAX_CONCURRENT_STREAMS limit. */
   nghttp2_outbound_queue ob_syn;
+  /* Queues for DATA frames which is used when
+     SETTINGS_NO_RFC7540_PRIORITIES is enabled.  This implements RFC
+     9218 extensible prioritization scheme. */
+  struct {
+    nghttp2_pq ob_data;
+  } sched[NGHTTP2_EXTPRI_URGENCY_LEVELS];
   nghttp2_active_outbound_item aob;
   nghttp2_inbound_frame iframe;
   nghttp2_hd_deflater hd_deflater;
@@ -227,6 +235,9 @@ struct nghttp2_session {
   /* Queue of In-flight SETTINGS values.  SETTINGS bearing ACK is not
      considered as in-flight. */
   nghttp2_inflight_settings *inflight_settings_head;
+  /* Sequential number across all streams to process streams in
+     FIFO. */
+  uint64_t stream_seq;
   /* The number of outgoing streams. This will be capped by
      remote_settings.max_concurrent_streams. */
   size_t num_outgoing_streams;
@@ -267,6 +278,8 @@ struct nghttp2_session {
   /* The maximum length of header block to send.  Calculated by the
      same way as nghttp2_hd_deflate_bound() does. */
   size_t max_send_header_block_length;
+  /* The maximum number of settings accepted per SETTINGS frame. */
+  size_t max_settings;
   /* Next Stream ID. Made unsigned int to detect >= (1 << 31). */
   uint32_t next_stream_id;
   /* The last stream ID this session initiated.  For client session,
@@ -326,6 +339,11 @@ struct nghttp2_session {
   /* Unacked local ENABLE_CONNECT_PROTOCOL value.  We use this to
      accept :protocol header field before SETTINGS_ACK is received. */
   uint8_t pending_enable_connect_protocol;
+  /* Unacked local SETTINGS_NO_RFC7540_PRIORITIES value, which is
+     effective before it is acknowledged. */
+  uint8_t pending_no_rfc7540_priorities;
+  /* Turn on fallback to RFC 7540 priorities; for server use only. */
+  uint8_t fallback_rfc7540_priorities;
   /* Nonzero if the session is server side. */
   uint8_t server;
   /* Flags indicating GOAWAY is sent and/or received. The flags are
@@ -406,7 +424,7 @@ int nghttp2_session_add_rst_stream(nghttp2_session *session, int32_t stream_id,
                                    uint32_t error_code);
 
 /*
- * Adds PING frame. This is a convenient functin built on top of
+ * Adds PING frame. This is a convenient function built on top of
  * nghttp2_session_add_frame() to add PING easily.
  *
  * If the |opaque_data| is not NULL, it must point to 8 bytes memory
@@ -772,6 +790,19 @@ int nghttp2_session_on_origin_received(nghttp2_session *session,
                                        nghttp2_frame *frame);
 
 /*
+ * Called when PRIORITY_UPDATE is received, assuming |frame| is
+ * properly initialized.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGHTTP2_ERR_CALLBACK_FAILURE
+ *     The callback function failed.
+ */
+int nghttp2_session_on_priority_update_received(nghttp2_session *session,
+                                                nghttp2_frame *frame);
+
+/*
  * Called when DATA is received, assuming |frame| is properly
  * initialized.
  *
@@ -898,4 +929,36 @@ int nghttp2_session_terminate_session_with_reason(nghttp2_session *session,
                                                   uint32_t error_code,
                                                   const char *reason);
 
+/*
+ * Accumulates received bytes |delta_size| for connection-level flow
+ * control and decides whether to send WINDOW_UPDATE to the
+ * connection.  If NGHTTP2_OPT_NO_AUTO_WINDOW_UPDATE is set,
+ * WINDOW_UPDATE will not be sent.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGHTTP2_ERR_NOMEM
+ *     Out of memory.
+ */
+int nghttp2_session_update_recv_connection_window_size(nghttp2_session *session,
+                                                       size_t delta_size);
+
+/*
+ * Accumulates received bytes |delta_size| for stream-level flow
+ * control and decides whether to send WINDOW_UPDATE to that stream.
+ * If NGHTTP2_OPT_NO_AUTO_WINDOW_UPDATE is set, WINDOW_UPDATE will not
+ * be sent.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGHTTP2_ERR_NOMEM
+ *     Out of memory.
+ */
+int nghttp2_session_update_recv_stream_window_size(nghttp2_session *session,
+                                                   nghttp2_stream *stream,
+                                                   size_t delta_size,
+                                                   int send_window_update);
+
 #endif /* NGHTTP2_SESSION_H */
diff --git a/Utilities/cmnghttp2/lib/nghttp2_stream.c b/Utilities/cmnghttp2/lib/nghttp2_stream.c
index dc3a6b11cc..b3614a0b02 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_stream.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_stream.c
@@ -33,7 +33,7 @@
 #include "nghttp2_frame.h"
 
 /* Maximum distance between any two stream's cycle in the same
-   prirority queue.  Imagine stream A's cycle is A, and stream B's
+   priority queue.  Imagine stream A's cycle is A, and stream B's
    cycle is B, and A < B.  The cycle is unsigned 32 bit integer, it
    may get overflow.  Because of how we calculate the next cycle
    value, if B - A is less than or equals to
@@ -62,7 +62,6 @@ void nghttp2_stream_init(nghttp2_stream *stream, int32_t stream_id,
                          int32_t weight, int32_t remote_initial_window_size,
                          int32_t local_initial_window_size,
                          void *stream_user_data, nghttp2_mem *mem) {
-  nghttp2_map_entry_init(&stream->map_entry, (key_type)stream_id);
   nghttp2_pq_init(&stream->obq, stream_less, mem);
 
   stream->stream_id = stream_id;
@@ -101,6 +100,8 @@ void nghttp2_stream_init(nghttp2_stream *stream, int32_t stream_id,
   stream->descendant_next_seq = 0;
   stream->seq = 0;
   stream->last_writelen = 0;
+
+  stream->extpri = stream->http_extpri = NGHTTP2_EXTPRI_DEFAULT_URGENCY;
 }
 
 void nghttp2_stream_free(nghttp2_stream *stream) {
@@ -485,6 +486,10 @@ int nghttp2_stream_attach_item(nghttp2_stream *stream,
 
   stream->item = item;
 
+  if (stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) {
+    return 0;
+  }
+
   rv = stream_update_dep_on_attach_item(stream);
   if (rv != 0) {
     /* This may relave stream->queued == 1, but stream->item == NULL.
@@ -504,6 +509,10 @@ int nghttp2_stream_detach_item(nghttp2_stream *stream) {
   stream->item = NULL;
   stream->flags = (uint8_t)(stream->flags & ~NGHTTP2_STREAM_FLAG_DEFERRED_ALL);
 
+  if (stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) {
+    return 0;
+  }
+
   return stream_update_dep_on_detach_item(stream);
 }
 
@@ -515,6 +524,10 @@ int nghttp2_stream_defer_item(nghttp2_stream *stream, uint8_t flags) {
 
   stream->flags |= flags;
 
+  if (stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) {
+    return 0;
+  }
+
   return stream_update_dep_on_detach_item(stream);
 }
 
@@ -530,6 +543,10 @@ int nghttp2_stream_resume_deferred_item(nghttp2_stream *stream, uint8_t flags) {
     return 0;
   }
 
+  if (stream->flags & NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES) {
+    return 0;
+  }
+
   return stream_update_dep_on_attach_item(stream);
 }
 
diff --git a/Utilities/cmnghttp2/lib/nghttp2_stream.h b/Utilities/cmnghttp2/lib/nghttp2_stream.h
index a1b807d295..7a8e4c6c1d 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_stream.h
+++ b/Utilities/cmnghttp2/lib/nghttp2_stream.h
@@ -90,8 +90,15 @@ typedef enum {
   NGHTTP2_STREAM_FLAG_DEFERRED_USER = 0x08,
   /* bitwise OR of NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL and
      NGHTTP2_STREAM_FLAG_DEFERRED_USER. */
-  NGHTTP2_STREAM_FLAG_DEFERRED_ALL = 0x0c
-
+  NGHTTP2_STREAM_FLAG_DEFERRED_ALL = 0x0c,
+  /* Indicates that this stream is not subject to RFC7540
+     priorities scheme. */
+  NGHTTP2_STREAM_FLAG_NO_RFC7540_PRIORITIES = 0x10,
+  /* Ignore client RFC 9218 priority signal. */
+  NGHTTP2_STREAM_FLAG_IGNORE_CLIENT_PRIORITIES = 0x20,
+  /* Indicates that RFC 9113 leading and trailing white spaces
+     validation against a field value is not performed. */
+  NGHTTP2_STREAM_FLAG_NO_RFC9113_LEADING_AND_TRAILING_WS_VALIDATION = 0x40,
 } nghttp2_stream_flag;
 
 /* HTTP related flags to enforce HTTP semantics */
@@ -132,11 +139,14 @@ typedef enum {
   /* set if final response is expected */
   NGHTTP2_HTTP_FLAG_EXPECT_FINAL_RESPONSE = 1 << 14,
   NGHTTP2_HTTP_FLAG__PROTOCOL = 1 << 15,
+  /* set if priority header field is received */
+  NGHTTP2_HTTP_FLAG_PRIORITY = 1 << 16,
+  /* set if an error is encountered while parsing priority header
+     field */
+  NGHTTP2_HTTP_FLAG_BAD_PRIORITY = 1 << 17,
 } nghttp2_http_flag;
 
 struct nghttp2_stream {
-  /* Intrusive Map */
-  nghttp2_map_entry map_entry;
   /* Entry for dep_prev->obq */
   nghttp2_pq_entry pq_entry;
   /* Priority Queue storing direct descendant (nghttp2_stream).  Only
@@ -206,7 +216,7 @@ struct nghttp2_stream {
   /* status code from remote server */
   int16_t status_code;
   /* Bitwise OR of zero or more nghttp2_http_flag values */
-  uint16_t http_flags;
+  uint32_t http_flags;
   /* This is bitwise-OR of 0 or more of nghttp2_stream_flag. */
   uint8_t flags;
   /* Bitwise OR of zero or more nghttp2_shut_flag values */
@@ -220,6 +230,12 @@ struct nghttp2_stream {
      this stream.  The nonzero does not necessarily mean WINDOW_UPDATE
      is not queued. */
   uint8_t window_update_queued;
+  /* extpri is a stream priority produced by nghttp2_extpri_to_uint8
+     used by RFC 9218 extensible priorities. */
+  uint8_t extpri;
+  /* http_extpri is a stream priority received in HTTP request header
+     fields and produced by nghttp2_extpri_to_uint8. */
+  uint8_t http_extpri;
 };
 
 void nghttp2_stream_init(nghttp2_stream *stream, int32_t stream_id,
diff --git a/Utilities/cmnghttp2/lib/nghttp2_submit.c b/Utilities/cmnghttp2/lib/nghttp2_submit.c
index f604eff5c9..f5554eb564 100644
--- a/Utilities/cmnghttp2/lib/nghttp2_submit.c
+++ b/Utilities/cmnghttp2/lib/nghttp2_submit.c
@@ -196,7 +196,8 @@ int32_t nghttp2_submit_headers(nghttp2_session *session, uint8_t flags,
 
   flags &= NGHTTP2_FLAG_END_STREAM;
 
-  if (pri_spec && !nghttp2_priority_spec_check_default(pri_spec)) {
+  if (pri_spec && !nghttp2_priority_spec_check_default(pri_spec) &&
+      session->remote_settings.no_rfc7540_priorities != 1) {
     rv = detect_self_dependency(session, stream_id, pri_spec);
     if (rv != 0) {
       return rv;
@@ -229,6 +230,10 @@ int nghttp2_submit_priority(nghttp2_session *session, uint8_t flags,
 
   mem = &session->mem;
 
+  if (session->remote_settings.no_rfc7540_priorities == 1) {
+    return 0;
+  }
+
   if (stream_id == 0 || pri_spec == NULL) {
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
@@ -450,6 +455,13 @@ int nghttp2_session_set_local_window_size(nghttp2_session *session,
     if (rv != 0) {
       return rv;
     }
+
+    if (window_size_increment > 0) {
+      return nghttp2_session_add_window_update(session, 0, stream_id,
+                                               window_size_increment);
+    }
+
+    return nghttp2_session_update_recv_connection_window_size(session, 0);
   } else {
     stream = nghttp2_session_get_stream(session, stream_id);
 
@@ -476,14 +488,15 @@ int nghttp2_session_set_local_window_size(nghttp2_session *session,
     if (rv != 0) {
       return rv;
     }
-  }
 
-  if (window_size_increment > 0) {
-    return nghttp2_session_add_window_update(session, 0, stream_id,
-                                             window_size_increment);
-  }
+    if (window_size_increment > 0) {
+      return nghttp2_session_add_window_update(session, 0, stream_id,
+                                               window_size_increment);
+    }
 
-  return 0;
+    return nghttp2_session_update_recv_stream_window_size(session, stream, 0,
+                                                          1);
+  }
 }
 
 int nghttp2_submit_altsvc(nghttp2_session *session, uint8_t flags,
@@ -654,6 +667,78 @@ fail_item_malloc:
   return rv;
 }
 
+int nghttp2_submit_priority_update(nghttp2_session *session, uint8_t flags,
+                                   int32_t stream_id,
+                                   const uint8_t *field_value,
+                                   size_t field_value_len) {
+  nghttp2_mem *mem;
+  uint8_t *buf, *p;
+  nghttp2_outbound_item *item;
+  nghttp2_frame *frame;
+  nghttp2_ext_priority_update *priority_update;
+  int rv;
+  (void)flags;
+
+  mem = &session->mem;
+
+  if (session->server) {
+    return NGHTTP2_ERR_INVALID_STATE;
+  }
+
+  if (session->remote_settings.no_rfc7540_priorities == 0) {
+    return 0;
+  }
+
+  if (stream_id == 0 || 4 + field_value_len > NGHTTP2_MAX_PAYLOADLEN) {
+    return NGHTTP2_ERR_INVALID_ARGUMENT;
+  }
+
+  if (field_value_len) {
+    buf = nghttp2_mem_malloc(mem, field_value_len + 1);
+    if (buf == NULL) {
+      return NGHTTP2_ERR_NOMEM;
+    }
+
+    p = nghttp2_cpymem(buf, field_value, field_value_len);
+    *p = '\0';
+  } else {
+    buf = NULL;
+  }
+
+  item = nghttp2_mem_malloc(mem, sizeof(nghttp2_outbound_item));
+  if (item == NULL) {
+    rv = NGHTTP2_ERR_NOMEM;
+    goto fail_item_malloc;
+  }
+
+  nghttp2_outbound_item_init(item);
+
+  item->aux_data.ext.builtin = 1;
+
+  priority_update = &item->ext_frame_payload.priority_update;
+
+  frame = &item->frame;
+  frame->ext.payload = priority_update;
+
+  nghttp2_frame_priority_update_init(&frame->ext, stream_id, buf,
+                                     field_value_len);
+
+  rv = nghttp2_session_add_item(session, item);
+  if (rv != 0) {
+    nghttp2_frame_priority_update_free(&frame->ext, mem);
+    nghttp2_mem_free(mem, item);
+
+    return rv;
+  }
+
+  return 0;
+
+fail_item_malloc:
+  free(buf);
+
+  return rv;
+}
+
 static uint8_t set_request_flags(const nghttp2_priority_spec *pri_spec,
                                  const nghttp2_data_provider *data_prd) {
   uint8_t flags = NGHTTP2_FLAG_NONE;
@@ -680,7 +765,8 @@ int32_t nghttp2_submit_request(nghttp2_session *session,
     return NGHTTP2_ERR_PROTO;
   }
 
-  if (pri_spec && !nghttp2_priority_spec_check_default(pri_spec)) {
+  if (pri_spec && !nghttp2_priority_spec_check_default(pri_spec) &&
+      session->remote_settings.no_rfc7540_priorities != 1) {
     rv = detect_self_dependency(session, -1, pri_spec);
     if (rv != 0) {
       return rv;