SERVER-41230 Update FCV constants throughout server code following 4.2 branch

SERVER-42162 Update Execution-related generic upgrade/downgrade references
SERVER-42642 Update Replication-related generic upgrade/downgrade references
SERVER-42592 Update Sharding-related generic upgrade/downgrade references
SERVER-42794 Update Query-related generic upgrade/downgrade references
SERVER-41545 Bump wire protocol version for 4.4

6 files changed, 85 insertions, 86 deletions

diff --git a/src/mongo/db/commands/feature_compatibility_version.cpp b/src/mongo/db/commands/feature_compatibility_version.cpp
index ec1d65deb3b..0a7482078b4 100644
--- a/src/mongo/db/commands/feature_compatibility_version.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version.cpp
@@ -69,9 +69,9 @@ void FeatureCompatibilityVersion::setTargetUpgrade(OperationContext* opCtx) {
     // Sets both 'version' and 'targetVersion' fields.
     _runUpdateCommand(opCtx, [](auto updateMods) {
         updateMods.append(FeatureCompatibilityVersionParser::kVersionField,
-                          FeatureCompatibilityVersionParser::kVersion40);
-        updateMods.append(FeatureCompatibilityVersionParser::kTargetVersionField,
                           FeatureCompatibilityVersionParser::kVersion42);
+        updateMods.append(FeatureCompatibilityVersionParser::kTargetVersionField,
+                          FeatureCompatibilityVersionParser::kVersion44);
     });
 }
 
@@ -79,9 +79,9 @@ void FeatureCompatibilityVersion::setTargetDowngrade(OperationContext* opCtx) {
     // Sets both 'version' and 'targetVersion' fields.
     _runUpdateCommand(opCtx, [](auto updateMods) {
         updateMods.append(FeatureCompatibilityVersionParser::kVersionField,
-                          FeatureCompatibilityVersionParser::kVersion40);
+                          FeatureCompatibilityVersionParser::kVersion42);
         updateMods.append(FeatureCompatibilityVersionParser::kTargetVersionField,
-                          FeatureCompatibilityVersionParser::kVersion40);
+                          FeatureCompatibilityVersionParser::kVersion42);
     });
 }
 
@@ -124,8 +124,8 @@ void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* opCtx,
         repl::TimestampedBSONObj{
             BSON("_id" << FeatureCompatibilityVersionParser::kParameterName
                        << FeatureCompatibilityVersionParser::kVersionField
-                       << (storeUpgradeVersion ? FeatureCompatibilityVersionParser::kVersion42
-                                               : FeatureCompatibilityVersionParser::kVersion40)),
+                       << (storeUpgradeVersion ? FeatureCompatibilityVersionParser::kVersion44
+                                               : FeatureCompatibilityVersionParser::kVersion42)),
             Timestamp()},
         repl::OpTime::kUninitializedTerm));  // No timestamp or term because this write is not
                                              // replicated.
@@ -165,7 +165,7 @@ void FeatureCompatibilityVersion::onInsertOrUpdate(OperationContext* opCtx, cons
         serverGlobalParams.featureCompatibility.setVersion(newVersion);
         updateMinWireVersion();
 
-        if (newVersion != ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40) {
+        if (newVersion != ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo42) {
             // Close all incoming connections from internal clients with binary versions lower than
             // ours.
             opCtx->getServiceContext()->getServiceEntryPoint()->endAllSessions(
@@ -176,7 +176,7 @@ void FeatureCompatibilityVersion::onInsertOrUpdate(OperationContext* opCtx, cons
                 .dropConnections(transport::Session::kKeepOpen);
         }
 
-        if (newVersion != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) {
+        if (newVersion != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44) {
             if (MONGO_FAIL_POINT(hangBeforeAbortingRunningTransactionsOnFCVDowngrade)) {
                 log() << "featureCompatibilityVersion - "
                          "hangBeforeAbortingRunningTransactionsOnFCVDowngrade fail point enabled. "
@@ -196,17 +196,17 @@ void FeatureCompatibilityVersion::updateMinWireVersion() {
     WireSpec& spec = WireSpec::instance();
 
     switch (serverGlobalParams.featureCompatibility.getVersion()) {
-        case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42:
-        case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42:
-        case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40:
+        case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44:
+        case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo44:
+        case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo42:
             spec.incomingInternalClient.minWireVersion = LATEST_WIRE_VERSION;
             spec.outgoing.minWireVersion = LATEST_WIRE_VERSION;
             return;
-        case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40:
+        case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo42:
             spec.incomingInternalClient.minWireVersion = LATEST_WIRE_VERSION - 1;
             spec.outgoing.minWireVersion = LATEST_WIRE_VERSION - 1;
             return;
-        case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior:
+        case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault42Behavior:
             // getVersion() does not return this value.
             MONGO_UNREACHABLE;
     }
@@ -215,11 +215,11 @@ void FeatureCompatibilityVersion::updateMinWireVersion() {
 void FeatureCompatibilityVersion::_validateVersion(StringData version) {
     uassert(40284,
             str::stream() << "featureCompatibilityVersion must be '"
-                          << FeatureCompatibilityVersionParser::kVersion42 << "' or '"
-                          << FeatureCompatibilityVersionParser::kVersion40 << "'. See "
+                          << FeatureCompatibilityVersionParser::kVersion44 << "' or '"
+                          << FeatureCompatibilityVersionParser::kVersion42 << "'. See "
                           << feature_compatibility_version_documentation::kCompatibilityLink << ".",
-            version == FeatureCompatibilityVersionParser::kVersion42 ||
-                version == FeatureCompatibilityVersionParser::kVersion40);
+            version == FeatureCompatibilityVersionParser::kVersion44 ||
+                version == FeatureCompatibilityVersionParser::kVersion42);
 }
 
 void FeatureCompatibilityVersion::_runUpdateCommand(OperationContext* opCtx,
@@ -275,33 +275,33 @@ void FeatureCompatibilityVersionParameter::append(OperationContext* opCtx,
 
     BSONObjBuilder featureCompatibilityVersionBuilder(b.subobjStart(name));
     switch (serverGlobalParams.featureCompatibility.getVersion()) {
-        case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42:
+        case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44:
             featureCompatibilityVersionBuilder.append(
                 FeatureCompatibilityVersionParser::kVersionField,
-                FeatureCompatibilityVersionParser::kVersion42);
+                FeatureCompatibilityVersionParser::kVersion44);
             return;
-        case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42:
+        case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo44:
             featureCompatibilityVersionBuilder.append(
                 FeatureCompatibilityVersionParser::kVersionField,
-                FeatureCompatibilityVersionParser::kVersion40);
+                FeatureCompatibilityVersionParser::kVersion42);
             featureCompatibilityVersionBuilder.append(
                 FeatureCompatibilityVersionParser::kTargetVersionField,
-                FeatureCompatibilityVersionParser::kVersion42);
+                FeatureCompatibilityVersionParser::kVersion44);
             return;
-        case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40:
+        case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo42:
             featureCompatibilityVersionBuilder.append(
                 FeatureCompatibilityVersionParser::kVersionField,
-                FeatureCompatibilityVersionParser::kVersion40);
+                FeatureCompatibilityVersionParser::kVersion42);
             featureCompatibilityVersionBuilder.append(
                 FeatureCompatibilityVersionParser::kTargetVersionField,
-                FeatureCompatibilityVersionParser::kVersion40);
+                FeatureCompatibilityVersionParser::kVersion42);
             return;
-        case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40:
+        case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo42:
             featureCompatibilityVersionBuilder.append(
                 FeatureCompatibilityVersionParser::kVersionField,
-                FeatureCompatibilityVersionParser::kVersion40);
+                FeatureCompatibilityVersionParser::kVersion42);
             return;
-        case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior:
+        case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault42Behavior:
             // getVersion() does not return this value.
             MONGO_UNREACHABLE;
     }
diff --git a/src/mongo/db/commands/feature_compatibility_version.h b/src/mongo/db/commands/feature_compatibility_version.h
index c6f7a7f97d8..1c650fa1f0d 100644
--- a/src/mongo/db/commands/feature_compatibility_version.h
+++ b/src/mongo/db/commands/feature_compatibility_version.h
@@ -52,24 +52,23 @@ public:
     static Lock::ResourceMutex fcvLock;
 
     /**
-     * Records intent to perform a 4.0 -> 4.2 upgrade by updating the on-disk feature
-     * compatibility version document to have 'version'=4.0, 'targetVersion'=4.2.
+     * Records intent to perform a 4.2 -> 4.4 upgrade by updating the on-disk feature
+     * compatibility version document to have 'version'=4.2, 'targetVersion'=4.4.
      * Should be called before schemas are modified.
      */
     static void setTargetUpgrade(OperationContext* opCtx);
 
     /**
-     * Records intent to perform a 4.2 -> 4.0 downgrade by updating the on-disk feature
-     * compatibility version document to have 'version'=4.0, 'targetVersion'=4.0.
+     * Records intent to perform a 4.4 -> 4.2 downgrade by updating the on-disk feature
+     * compatibility version document to have 'version'=4.2, 'targetVersion'=4.2.
      * Should be called before schemas are modified.
      */
     static void setTargetDowngrade(OperationContext* opCtx);
 
     /**
-     * Records the completion of a 4.0 <-> 4.2 upgrade or downgrade by updating the on-disk feature
+     * Records the completion of a 4.2 <-> 4.4 upgrade or downgrade by updating the on-disk feature
      * compatibility version document to have 'version'=version and unsetting the 'targetVersion'
-     * field.
-     * Should be called after schemas are modified.
+     * field. Should be called after schemas are modified.
      */
     static void unsetTargetUpgradeOrDowngrade(OperationContext* opCtx, StringData version);
 
diff --git a/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp b/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
index 919a2aae34c..1450e35ece6 100644
--- a/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
@@ -77,12 +77,12 @@ StatusWith<std::string> FeatureCompatibilityVersionCommandParser::extractVersion
 
     const std::string version = versionElem.String();
 
-    if (version != FeatureCompatibilityVersionParser::kVersion42 &&
-        version != FeatureCompatibilityVersionParser::kVersion40) {
+    if (version != FeatureCompatibilityVersionParser::kVersion44 &&
+        version != FeatureCompatibilityVersionParser::kVersion42) {
         return {ErrorCodes::BadValue,
                 str::stream() << "Invalid command argument. Expected '"
-                              << FeatureCompatibilityVersionParser::kVersion42 << "' or '"
-                              << FeatureCompatibilityVersionParser::kVersion40 << "', found "
+                              << FeatureCompatibilityVersionParser::kVersion44 << "' or '"
+                              << FeatureCompatibilityVersionParser::kVersion42 << "', found "
                               << version << " in: " << cmdObj << ". See "
                               << feature_compatibility_version_documentation::kCompatibilityLink
                               << "."};
diff --git a/src/mongo/db/commands/feature_compatibility_version_parser.cpp b/src/mongo/db/commands/feature_compatibility_version_parser.cpp
index 0aa872b9041..d542d23c7a3 100644
--- a/src/mongo/db/commands/feature_compatibility_version_parser.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version_parser.cpp
@@ -38,10 +38,10 @@
 
 namespace mongo {
 
-constexpr StringData FeatureCompatibilityVersionParser::kVersion40;
 constexpr StringData FeatureCompatibilityVersionParser::kVersion42;
-constexpr StringData FeatureCompatibilityVersionParser::kVersionDowngradingTo40;
-constexpr StringData FeatureCompatibilityVersionParser::kVersionUpgradingTo42;
+constexpr StringData FeatureCompatibilityVersionParser::kVersion44;
+constexpr StringData FeatureCompatibilityVersionParser::kVersionDowngradingTo42;
+constexpr StringData FeatureCompatibilityVersionParser::kVersionUpgradingTo44;
 constexpr StringData FeatureCompatibilityVersionParser::kVersionUnset;
 
 constexpr StringData FeatureCompatibilityVersionParser::kParameterName;
@@ -51,7 +51,7 @@ constexpr StringData FeatureCompatibilityVersionParser::kTargetVersionField;
 StatusWith<ServerGlobalParams::FeatureCompatibility::Version>
 FeatureCompatibilityVersionParser::parse(const BSONObj& featureCompatibilityVersionDoc) {
     ServerGlobalParams::FeatureCompatibility::Version version =
-        ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior;
+        ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault42Behavior;
     std::string versionString;
     std::string targetVersionString;
 
@@ -72,12 +72,12 @@ FeatureCompatibilityVersionParser::parse(const BSONObj& featureCompatibilityVers
                                   << ".");
             }
 
-            if (elem.String() != kVersion42 && elem.String() != kVersion40) {
+            if (elem.String() != kVersion44 && elem.String() != kVersion42) {
                 return Status(ErrorCodes::BadValue,
                               str::stream()
                                   << "Invalid value for " << fieldName << ", found "
-                                  << elem.String() << ", expected '" << kVersion42 << "' or '"
-                                  << kVersion40 << "'. Contents of " << kParameterName
+                                  << elem.String() << ", expected '" << kVersion44 << "' or '"
+                                  << kVersion42 << "'. Contents of " << kParameterName
                                   << " document in "
                                   << NamespaceString::kServerConfigurationNamespace.toString()
                                   << ": " << featureCompatibilityVersionDoc << ". See "
@@ -102,16 +102,16 @@ FeatureCompatibilityVersionParser::parse(const BSONObj& featureCompatibilityVers
         }
     }
 
-    if (versionString == kVersion40) {
-        if (targetVersionString == kVersion42) {
-            version = ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42;
-        } else if (targetVersionString == kVersion40) {
-            version = ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40;
+    if (versionString == kVersion42) {
+        if (targetVersionString == kVersion44) {
+            version = ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo44;
+        } else if (targetVersionString == kVersion42) {
+            version = ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo42;
         } else {
-            version = ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40;
+            version = ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo42;
         }
-    } else if (versionString == kVersion42) {
-        if (targetVersionString == kVersion42 || targetVersionString == kVersion40) {
+    } else if (versionString == kVersion44) {
+        if (targetVersionString == kVersion44 || targetVersionString == kVersion42) {
             return Status(ErrorCodes::BadValue,
                           str::stream()
                               << "Invalid state for " << kParameterName << " document in "
@@ -120,7 +120,7 @@ FeatureCompatibilityVersionParser::parse(const BSONObj& featureCompatibilityVers
                               << feature_compatibility_version_documentation::kCompatibilityLink
                               << ".");
         } else {
-            version = ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42;
+            version = ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44;
         }
     } else {
         return Status(ErrorCodes::BadValue,
diff --git a/src/mongo/db/commands/feature_compatibility_version_parser.h b/src/mongo/db/commands/feature_compatibility_version_parser.h
index f563e09af2c..757d725a0bf 100644
--- a/src/mongo/db/commands/feature_compatibility_version_parser.h
+++ b/src/mongo/db/commands/feature_compatibility_version_parser.h
@@ -40,10 +40,10 @@ namespace mongo {
  */
 class FeatureCompatibilityVersionParser {
 public:
-    static constexpr StringData kVersion40 = "4.0"_sd;
     static constexpr StringData kVersion42 = "4.2"_sd;
-    static constexpr StringData kVersionDowngradingTo40 = "downgrading to 4.0"_sd;
-    static constexpr StringData kVersionUpgradingTo42 = "upgrading to 4.2"_sd;
+    static constexpr StringData kVersion44 = "4.4"_sd;
+    static constexpr StringData kVersionDowngradingTo42 = "downgrading to 4.2"_sd;
+    static constexpr StringData kVersionUpgradingTo44 = "upgrading to 4.4"_sd;
     static constexpr StringData kVersionUnset = "Unset"_sd;
 
     static constexpr StringData kParameterName = "featureCompatibilityVersion"_sd;
@@ -63,16 +63,16 @@ public:
      */
     static StringData toString(ServerGlobalParams::FeatureCompatibility::Version version) {
         switch (version) {
-            case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior:
+            case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault42Behavior:
                 return kVersionUnset;
-            case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40:
-                return kVersion40;
-            case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42:
-                return kVersionUpgradingTo42;
-            case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40:
-                return kVersionDowngradingTo40;
-            case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42:
+            case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo42:
                 return kVersion42;
+            case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo44:
+                return kVersionUpgradingTo44;
+            case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo42:
+                return kVersionDowngradingTo42;
+            case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44:
+                return kVersion44;
             default:
                 MONGO_UNREACHABLE;
         }
diff --git a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
index 0238f1bf004..cfe59311ab4 100644
--- a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
+++ b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
@@ -62,7 +62,7 @@ MONGO_FAIL_POINT_DEFINE(featureCompatibilityDowngrade);
 MONGO_FAIL_POINT_DEFINE(featureCompatibilityUpgrade);
 
 /**
- * Sets the minimum allowed version for the cluster. If it is 4.0, then the node should not use 4.2
+ * Sets the minimum allowed version for the cluster. If it is 4.2, then the node should not use 4.4
  * features.
  *
  * Format:
@@ -88,13 +88,13 @@ public:
     }
 
     std::string help() const override {
+        using FCVP = FeatureCompatibilityVersionParser;
         std::stringstream h;
-        h << "Set the API version exposed by this node. If set to \""
-          << FeatureCompatibilityVersionParser::kVersion40
-          << "\", then 4.2 features are disabled. If \""
-          << FeatureCompatibilityVersionParser::kVersion42
-          << "\", then 4.2 features are enabled, and all nodes in the cluster must be binary "
-             "version 4.2. See "
+        h << "Set the API version exposed by this node. If set to '" << FCVP::kVersion42
+          << "', then " << FCVP::kVersion44 << " features are disabled. If set to '"
+          << FCVP::kVersion44 << "', then " << FCVP::kVersion44
+          << " features are enabled, and all nodes in the cluster must be binary version "
+          << FCVP::kVersion44 << ". See "
           << feature_compatibility_version_documentation::kCompatibilityLink << ".";
         return h.str();
     }
@@ -143,16 +143,16 @@ public:
         ServerGlobalParams::FeatureCompatibility::Version actualVersion =
             serverGlobalParams.featureCompatibility.getVersion();
 
-        if (requestedVersion == FeatureCompatibilityVersionParser::kVersion42) {
+        if (requestedVersion == FeatureCompatibilityVersionParser::kVersion44) {
             uassert(ErrorCodes::IllegalOperation,
-                    "cannot initiate featureCompatibilityVersion upgrade to 4.2 while a previous "
-                    "featureCompatibilityVersion downgrade to 4.0 has not completed. Finish "
-                    "downgrade to 4.0, then upgrade to 4.2.",
+                    "cannot initiate featureCompatibilityVersion upgrade to 4.4 while a previous "
+                    "featureCompatibilityVersion downgrade to 4.2 has not completed. Finish "
+                    "downgrade to 4.2, then upgrade to 4.4.",
                     actualVersion !=
-                        ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40);
+                        ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo42);
 
             if (actualVersion ==
-                ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) {
+                ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44) {
                 // Set the client's last opTime to the system last opTime so no-ops wait for
                 // writeConcern.
                 repl::ReplClientInfo::forClient(opCtx->getClient())
@@ -166,7 +166,7 @@ public:
                 // Take the global lock in S mode to create a barrier for operations taking the
                 // global IX or X locks. This ensures that either
                 //   - The global IX/X locked operation will start after the FCV change, see the
-                //     upgrading to 4.2 FCV and act accordingly.
+                //     upgrading to 4.4 FCV and act accordingly.
                 //   - The global IX/X locked operation began prior to the FCV change, is acting on
                 //     that assumption and will finish before upgrade procedures begin right after
                 //     this.
@@ -186,15 +186,15 @@ public:
             }
 
             FeatureCompatibilityVersion::unsetTargetUpgradeOrDowngrade(opCtx, requestedVersion);
-        } else if (requestedVersion == FeatureCompatibilityVersionParser::kVersion40) {
+        } else if (requestedVersion == FeatureCompatibilityVersionParser::kVersion42) {
             uassert(ErrorCodes::IllegalOperation,
-                    "cannot initiate setting featureCompatibilityVersion to 4.0 while a previous "
-                    "featureCompatibilityVersion upgrade to 4.2 has not completed.",
+                    "cannot initiate setting featureCompatibilityVersion to 4.2 while a previous "
+                    "featureCompatibilityVersion upgrade to 4.4 has not completed.",
                     actualVersion !=
-                        ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42);
+                        ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo44);
 
             if (actualVersion ==
-                ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40) {
+                ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo42) {
                 // Set the client's last opTime to the system last opTime so no-ops wait for
                 // writeConcern.
                 repl::ReplClientInfo::forClient(opCtx->getClient())
@@ -208,7 +208,7 @@ public:
                 // Take the global lock in S mode to create a barrier for operations taking the
                 // global IX or X locks. This ensures that either
                 //   - The global IX/X locked operation will start after the FCV change, see the
-                //     downgrading to 4.0 FCV and act accordingly.
+                //     downgrading to 4.2 FCV and act accordingly.
                 //   - The global IX/X locked operation began prior to the FCV change, is acting on
                 //     that assumption and will finish before downgrade procedures begin right after
                 //     this.