From 0b62acd9868ac597749650c837618fcc5a18f832 Mon Sep 17 00:00:00 2001
From: frazze-jobb <frazze@erlang.org>
Date: Thu, 11 May 2023 17:37:46 +0200
Subject: stdlib: update doc regarding escript raw bytes incompatibility

---
 erts/doc/src/escript_cmd.xml | 5 +++--
 lib/stdlib/doc/src/io.xml    | 9 +++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/erts/doc/src/escript_cmd.xml b/erts/doc/src/escript_cmd.xml
index 78b121ee97..06c245006b 100644
--- a/erts/doc/src/escript_cmd.xml
+++ b/erts/doc/src/escript_cmd.xml
@@ -118,9 +118,10 @@ $ <input>escript factorial 5</input></pre>
             applies to the script itself. The encoding of the
             I/O-server, however, must be set explicitly as follows:</p>
           <code>
-io:setopts([{encoding, unicode}])</code>
+io:setopts([{encoding, latin1}])</code>
           <p>The default encoding of the I/O-server for <c>standard_io</c>
-            is <c>latin1</c>, as the script runs in a non-interactive terminal
+            is <c>unicode</c> if its supported, as the script runs in a
+            non-interactive terminal.
             (see section
             <seeguide marker="stdlib:unicode_usage#unicode_options_summary">
             Summary of Options</seeguide>) in the STDLIB User's Guide.</p>
diff --git a/lib/stdlib/doc/src/io.xml b/lib/stdlib/doc/src/io.xml
index a1c467ca1c..2a25163e3a 100644
--- a/lib/stdlib/doc/src/io.xml
+++ b/lib/stdlib/doc/src/io.xml
@@ -1157,6 +1157,15 @@ enter><input>1.0er.</input>
             <p>This option is supported by the standard shell
               (<c>group.erl</c>), the 'oldshell' (<c>user.erl</c>), and the
               file I/O servers.</p>
+            <note>
+              Since OTP 26 <c>user.erl</c> has been deprecated, all I/O is now passed
+              through <c>group.erl</c>. I/O defaults to unicode if its supported, otherwise
+              latin1 (0-127), all text is however converted to unicode as an intermediate
+              representation. This means that 128-255 will be converted to unicode.
+              If you have an escript that sends raw bytes on standard_io, those bytes
+              will be translated to unicode and then back to latin1.
+              To avoid this, set the encoding to latin1.
+            </note>
           </item>
           <tag><c>{echo, boolean()}</c></tag>
           <item>
-- 
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