SERVER-30745 Prohibit unsafe comparisons against featureCompatibilityVersion

50 files changed, 143 insertions, 178 deletions

diff --git a/src/mongo/db/auth/authorization_session_test.cpp b/src/mongo/db/auth/authorization_session_test.cpp
index 0ec66e94598..9fb7effb64c 100644
--- a/src/mongo/db/auth/authorization_session_test.cpp
+++ b/src/mongo/db/auth/authorization_session_test.cpp
@@ -93,7 +93,7 @@ public:
     std::unique_ptr<AuthorizationSessionForTest> authzSession;
 
     void setUp() {
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k36);
         session = transportLayer.createSession();
         client = serviceContext.makeClient("testClient", session);
diff --git a/src/mongo/db/auth/role_graph_test.cpp b/src/mongo/db/auth/role_graph_test.cpp
index 5301ab6f6aa..dcbe03002ca 100644
--- a/src/mongo/db/auth/role_graph_test.cpp
+++ b/src/mongo/db/auth/role_graph_test.cpp
@@ -774,7 +774,7 @@ TEST(RoleGraphTest, AddRoleFromDocument) {
         return builder.obj();
     };
 
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k36);
 
     RoleGraph graph;
diff --git a/src/mongo/db/auth/user_document_parser_test.cpp b/src/mongo/db/auth/user_document_parser_test.cpp
index 0ce0d378ea9..2eed6173e0a 100644
--- a/src/mongo/db/auth/user_document_parser_test.cpp
+++ b/src/mongo/db/auth/user_document_parser_test.cpp
@@ -231,7 +231,7 @@ public:
     V2UserDocumentParser v2parser;
 
     void setUp() {
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k36);
         user.reset(new User(UserName("spencer", "test")));
         adminUser.reset(new User(UserName("admin", "admin")));
@@ -645,7 +645,7 @@ TEST_F(V2UserDocumentParsing, V2AuthenticationRestrictionsExtraction) {
 }
 
 TEST_F(V2UserDocumentParsing, V2AuthenticationRestrictionsExtractionAndRetreival) {
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k36);
     enableIPv6(true);
     ASSERT_OK(v2parser.initializeAuthenticationRestrictionsFromUserDocument(
diff --git a/src/mongo/db/auth/user_management_commands_parser.cpp b/src/mongo/db/auth/user_management_commands_parser.cpp
index ec10ce928f7..f206ab72b34 100644
--- a/src/mongo/db/auth/user_management_commands_parser.cpp
+++ b/src/mongo/db/auth/user_management_commands_parser.cpp
@@ -192,8 +192,7 @@ Status parseCreateOrUpdateUserCommands(const BSONObj& cmdObj,
     validFieldNames.insert("digestPassword");
     validFieldNames.insert("pwd");
     validFieldNames.insert("roles");
-    if (serverGlobalParams.featureCompatibility.version.load() >=
-        ServerGlobalParams::FeatureCompatibility::Version::k36) {
+    if (serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         validFieldNames.insert("authenticationRestrictions");
     }
 
@@ -508,8 +507,7 @@ Status parseCreateOrUpdateRoleCommands(const BSONObj& cmdObj,
     validFieldNames.insert(cmdName.toString());
     validFieldNames.insert("privileges");
     validFieldNames.insert("roles");
-    if (serverGlobalParams.featureCompatibility.version.load() >=
-        ServerGlobalParams::FeatureCompatibility::Version::k36) {
+    if (serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         validFieldNames.insert("authenticationRestrictions");
     }
 
diff --git a/src/mongo/db/catalog/coll_mod.cpp b/src/mongo/db/catalog/coll_mod.cpp
index 2d7e6e60538..9badcf39050 100644
--- a/src/mongo/db/catalog/coll_mod.cpp
+++ b/src/mongo/db/catalog/coll_mod.cpp
@@ -173,11 +173,9 @@ StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
             MatchExpressionParser::AllowedFeatureSet allowedFeatures =
                 MatchExpressionParser::kBanAllSpecialFeatures;
             if (!serverGlobalParams.featureCompatibility.validateFeaturesAsMaster.load() ||
-                serverGlobalParams.featureCompatibility.version.load() !=
-                    ServerGlobalParams::FeatureCompatibility::Version::k34) {
-                // Allow $jsonSchema and $expr only if the feature compatibility version is newer
-                // than 3.4. Note that we don't enforce this restriction on secondary instances, as
-                // indicated by !validateFeaturesAsMaster.
+                serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
+                // Note that we don't enforce this restriction on the secondary or on backup
+                // instances, as indicated by !validateFeaturesAsMaster.
                 allowedFeatures |= MatchExpressionParser::kJSONSchema;
                 allowedFeatures |= MatchExpressionParser::kExpr;
             }
diff --git a/src/mongo/db/catalog/database_impl.cpp b/src/mongo/db/catalog/database_impl.cpp
index 096b7287e2d..161119ef16c 100644
--- a/src/mongo/db/catalog/database_impl.cpp
+++ b/src/mongo/db/catalog/database_impl.cpp
@@ -767,8 +767,7 @@ Collection* DatabaseImpl::createCollection(OperationContext* opCtx,
         auto coordinator = repl::ReplicationCoordinator::get(opCtx);
         bool okayCreation =
             (coordinator->getReplicationMode() != repl::ReplicationCoordinator::modeReplSet ||
-             serverGlobalParams.featureCompatibility.version.load() !=
-                 ServerGlobalParams::FeatureCompatibility::Version::k36 ||
+             !serverGlobalParams.featureCompatibility.isFullyUpgradedTo36() ||
              coordinator->canAcceptWritesForDatabase(opCtx, nss.db()) ||
              nss.isSystemDotProfile());  // system.profile is special as it's not replicated
         if (!okayCreation) {
@@ -799,7 +798,7 @@ Collection* DatabaseImpl::createCollection(OperationContext* opCtx,
             if (optionsWithUUID.autoIndexId == CollectionOptions::YES ||
                 optionsWithUUID.autoIndexId == CollectionOptions::DEFAULT) {
                 const auto featureCompatibilityVersion =
-                    serverGlobalParams.featureCompatibility.version.load();
+                    serverGlobalParams.featureCompatibility.getVersion();
                 IndexCatalog* ic = collection->getIndexCatalog();
                 fullIdIndexSpec = uassertStatusOK(ic->createIndexOnEmptyCollection(
                     opCtx,
@@ -1019,11 +1018,9 @@ auto mongo::userCreateNSImpl(OperationContext* opCtx,
         MatchExpressionParser::AllowedFeatureSet allowedFeatures =
             MatchExpressionParser::kBanAllSpecialFeatures;
         if (!serverGlobalParams.featureCompatibility.validateFeaturesAsMaster.load() ||
-            serverGlobalParams.featureCompatibility.version.load() !=
-                ServerGlobalParams::FeatureCompatibility::Version::k34) {
-            // $jsonSchema and $expr are only permitted when the feature compatibility version is
-            // newer than 3.4. Note that we don't enforce this feature compatibility check when we
-            // are on the secondary, as indicated by !validateFeaturesAsMaster.
+            serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
+            // Note that we don't enforce this feature compatibility check when we are on
+            // the secondary or on a backup instance, as indicated by !validateFeaturesAsMaster.
             allowedFeatures |= MatchExpressionParser::kJSONSchema;
             allowedFeatures |= MatchExpressionParser::kExpr;
         }
diff --git a/src/mongo/db/catalog/index_key_validate.cpp b/src/mongo/db/catalog/index_key_validate.cpp
index 0d48247f68d..0a8c30263b5 100644
--- a/src/mongo/db/catalog/index_key_validate.cpp
+++ b/src/mongo/db/catalog/index_key_validate.cpp
@@ -342,7 +342,7 @@ StatusWith<BSONObj> validateIndexSpec(
 
     if (!resolvedIndexVersion) {
         resolvedIndexVersion =
-            IndexDescriptor::getDefaultIndexVersion(featureCompatibility.version.load());
+            IndexDescriptor::getDefaultIndexVersion(featureCompatibility.getVersion());
     }
 
     if (!hasKeyPatternField) {
diff --git a/src/mongo/db/catalog/index_spec_validate_test.cpp b/src/mongo/db/catalog/index_spec_validate_test.cpp
index bb4cc4c1c1f..ca9179df5c4 100644
--- a/src/mongo/db/catalog/index_spec_validate_test.cpp
+++ b/src/mongo/db/catalog/index_spec_validate_test.cpp
@@ -65,7 +65,7 @@ BSONObj sorted(const BSONObj& obj) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfKeyPatternIsNotAnObject) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::TypeMismatch,
@@ -89,7 +89,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfKeyPatternIsNotAnObject) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfFieldRepeatedInKeyPattern) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::BadValue,
@@ -108,7 +108,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfFieldRepeatedInKeyPattern) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfKeyPatternIsNotPresent) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::FailedToParse,
@@ -120,7 +120,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfKeyPatternIsNotPresent) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfNameIsNotAString) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::TypeMismatch,
@@ -131,7 +131,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfNameIsNotAString) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfNameIsNotPresent) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(
@@ -141,7 +141,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfNameIsNotPresent) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfNamespaceIsNotAString) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::TypeMismatch,
@@ -162,7 +162,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfNamespaceIsNotAString) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfNamespaceIsEmptyString) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::BadValue,
@@ -176,7 +176,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfNamespaceIsEmptyString) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfNamespaceDoesNotMatch) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::BadValue,
@@ -200,7 +200,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfNamespaceDoesNotMatch) {
 
 TEST(IndexSpecValidateTest, ReturnsIndexSpecWithNamespaceFilledInIfItIsNotPresent) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
@@ -226,7 +226,7 @@ TEST(IndexSpecValidateTest, ReturnsIndexSpecWithNamespaceFilledInIfItIsNotPresen
 
 TEST(IndexSpecValidateTest, ReturnsIndexSpecUnchangedIfNamespaceAndVersionArePresent) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
@@ -251,7 +251,7 @@ TEST(IndexSpecValidateTest, ReturnsIndexSpecUnchangedIfNamespaceAndVersionArePre
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfVersionIsNotANumber) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::TypeMismatch,
@@ -272,7 +272,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfVersionIsNotANumber) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfVersionIsNotRepresentableAsInt) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::BadValue,
@@ -307,7 +307,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfVersionIsNotRepresentableAsInt) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfVersionIsV0) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::CannotCreateIndex,
@@ -321,7 +321,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfVersionIsV0) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfVersionIsUnsupported) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::CannotCreateIndex,
@@ -346,7 +346,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfVersionIsUnsupported) {
 
 TEST(IndexSpecValidateTest, AcceptsIndexVersionsThatAreAllowedForCreation) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
@@ -386,7 +386,7 @@ TEST(IndexSpecValidateTest, AcceptsIndexVersionsThatAreAllowedForCreation) {
 
 TEST(IndexSpecValidateTest, DefaultIndexVersionIsV2) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
@@ -412,7 +412,7 @@ TEST(IndexSpecValidateTest, DefaultIndexVersionIsV2) {
 
 TEST(IndexSpecValidateTest, AcceptsIndexVersionV1) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
@@ -435,7 +435,7 @@ TEST(IndexSpecValidateTest, AcceptsIndexVersionV1) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfCollationIsNotAnObject) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::TypeMismatch,
@@ -463,7 +463,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfCollationIsNotAnObject) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfCollationIsEmpty) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::BadValue,
@@ -477,7 +477,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfCollationIsEmpty) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfCollationIsPresentAndVersionIsLessThanV2) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     ASSERT_EQ(ErrorCodes::CannotCreateIndex,
@@ -494,7 +494,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfCollationIsPresentAndVersionIsLessTh
 
 TEST(IndexSpecValidateTest, AcceptsAnyNonEmptyObjectValueForCollation) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
@@ -544,7 +544,7 @@ TEST(IndexSpecValidateTest, AcceptsAnyNonEmptyObjectValueForCollation) {
 
 TEST(IndexSpecValidateTest, AcceptsIndexSpecIfCollationIsPresentAndVersionIsEqualToV2) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
@@ -573,7 +573,7 @@ TEST(IndexSpecValidateTest, AcceptsIndexSpecIfCollationIsPresentAndVersionIsEqua
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfUnknownFieldIsPresentInSpecV2) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
@@ -589,7 +589,7 @@ TEST(IndexSpecValidateTest, ReturnsAnErrorIfUnknownFieldIsPresentInSpecV2) {
 
 TEST(IndexSpecValidateTest, ReturnsAnErrorIfUnknownFieldIsPresentInSpecV1) {
     ServerGlobalParams::FeatureCompatibility featureCompatibility;
-    featureCompatibility.version.store(ServerGlobalParams::FeatureCompatibility::Version::k36);
+    featureCompatibility.setVersion(ServerGlobalParams::FeatureCompatibility::Version::k36);
     featureCompatibility.validateFeaturesAsMaster.store(true);
 
     auto result = validateIndexSpec(BSON("key" << BSON("field" << 1) << "name"
diff --git a/src/mongo/db/commands/dbcheck.cpp b/src/mongo/db/commands/dbcheck.cpp
index cf086a597ee..3650b93af48 100644
--- a/src/mongo/db/commands/dbcheck.cpp
+++ b/src/mongo/db/commands/dbcheck.cpp
@@ -538,8 +538,7 @@ public:
 
 private:
     bool _hasCorrectFCV(void) {
-        const auto fcv = serverGlobalParams.featureCompatibility.version.load();
-        return fcv >= ServerGlobalParams::FeatureCompatibility::Version::k36;
+        return serverGlobalParams.featureCompatibility.isFullyUpgradedTo36();
     }
 };
 
diff --git a/src/mongo/db/commands/drop_indexes.cpp b/src/mongo/db/commands/drop_indexes.cpp
index cc234d24d80..7f73d58557a 100644
--- a/src/mongo/db/commands/drop_indexes.cpp
+++ b/src/mongo/db/commands/drop_indexes.cpp
@@ -141,7 +141,7 @@ public:
         BackgroundOperation::assertNoBgOpInProgForNs(toReIndexNs.ns());
 
         const auto featureCompatibilityVersion =
-            serverGlobalParams.featureCompatibility.version.load();
+            serverGlobalParams.featureCompatibility.getVersion();
         const auto defaultIndexVersion =
             IndexDescriptor::getDefaultIndexVersion(featureCompatibilityVersion);
 
diff --git a/src/mongo/db/commands/end_sessions_command.cpp b/src/mongo/db/commands/end_sessions_command.cpp
index 895663a538c..3693c1971fd 100644
--- a/src/mongo/db/commands/end_sessions_command.cpp
+++ b/src/mongo/db/commands/end_sessions_command.cpp
@@ -60,8 +60,7 @@ public:
                                  const std::string& dbname,
                                  const BSONObj& cmdObj) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return SessionsCommandFCV34Status(getName());
         }
 
@@ -82,8 +81,7 @@ public:
                      const BSONObj& cmdObj,
                      BSONObjBuilder& result) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return appendCommandStatus(result, SessionsCommandFCV34Status(getName()));
         }
 
diff --git a/src/mongo/db/commands/feature_compatibility_version.cpp b/src/mongo/db/commands/feature_compatibility_version.cpp
index 3301bbe96a4..fa4f5346c48 100644
--- a/src/mongo/db/commands/feature_compatibility_version.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version.cpp
@@ -202,7 +202,7 @@ void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* opCtx,
 
             // We update the value of the version server parameter so that the admin.system.version
             // collection gets a UUID.
-            serverGlobalParams.featureCompatibility.targetVersion.store(
+            serverGlobalParams.featureCompatibility.setTargetVersion(
                 ServerGlobalParams::FeatureCompatibility::Version::k36);
 
             uassertStatusOK(storageInterface->createCollection(opCtx, nss, {}));
@@ -238,7 +238,7 @@ void FeatureCompatibilityVersion::onInsertOrUpdate(OperationContext* opCtx, cons
 
     // To avoid extra log messages when the targetVersion is set/unset, only log when the version
     // changes.
-    auto oldVersion = serverGlobalParams.featureCompatibility.version.load();
+    auto oldVersion = serverGlobalParams.featureCompatibility.getVersion();
     auto newVersion = versionInfo.version;
     if (oldVersion != newVersion) {
         log() << "setting featureCompatibilityVersion to " << toString(newVersion);
@@ -247,8 +247,8 @@ void FeatureCompatibilityVersion::onInsertOrUpdate(OperationContext* opCtx, cons
     // On commit, update the server parameters, and close any incoming connections with a wire
     // version that is below the minimum.
     opCtx->recoveryUnit()->onCommit([opCtx, versionInfo]() {
-        serverGlobalParams.featureCompatibility.version.store(versionInfo.version);
-        serverGlobalParams.featureCompatibility.targetVersion.store(versionInfo.targetVersion);
+        serverGlobalParams.featureCompatibility.setVersion(versionInfo.version);
+        serverGlobalParams.featureCompatibility.setTargetVersion(versionInfo.targetVersion);
 
         // Close all connections from internal clients with binary versions lower than 3.6.
         if (versionInfo.version == ServerGlobalParams::FeatureCompatibility::Version::k36 ||
@@ -269,9 +269,9 @@ void FeatureCompatibilityVersion::onDelete(OperationContext* opCtx, const BSONOb
     log() << "setting featureCompatibilityVersion to "
           << FeatureCompatibilityVersionCommandParser::kVersion34;
     opCtx->recoveryUnit()->onCommit([]() {
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k34);
-        serverGlobalParams.featureCompatibility.targetVersion.store(
+        serverGlobalParams.featureCompatibility.setTargetVersion(
             ServerGlobalParams::FeatureCompatibility::Version::kUnset);
     });
 }
@@ -280,9 +280,9 @@ void FeatureCompatibilityVersion::onDropCollection(OperationContext* opCtx) {
     log() << "setting featureCompatibilityVersion to "
           << FeatureCompatibilityVersionCommandParser::kVersion34;
     opCtx->recoveryUnit()->onCommit([]() {
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k34);
-        serverGlobalParams.featureCompatibility.targetVersion.store(
+        serverGlobalParams.featureCompatibility.setTargetVersion(
             ServerGlobalParams::FeatureCompatibility::Version::kUnset);
     });
 }
@@ -349,7 +349,7 @@ public:
     virtual void append(OperationContext* opCtx, BSONObjBuilder& b, const std::string& name) {
         b.append(name,
                  FeatureCompatibilityVersion::toString(
-                     serverGlobalParams.featureCompatibility.version.load()));
+                     serverGlobalParams.featureCompatibility.getVersion()));
     }
 
     virtual Status set(const BSONElement& newValueElement) {
diff --git a/src/mongo/db/commands/kill_all_sessions_by_pattern_command.cpp b/src/mongo/db/commands/kill_all_sessions_by_pattern_command.cpp
index c4147529484..30590d93739 100644
--- a/src/mongo/db/commands/kill_all_sessions_by_pattern_command.cpp
+++ b/src/mongo/db/commands/kill_all_sessions_by_pattern_command.cpp
@@ -73,8 +73,7 @@ public:
                                  const std::string& dbname,
                                  const BSONObj& cmdObj) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return SessionsCommandFCV34Status(getName());
         }
 
@@ -92,8 +91,7 @@ public:
                      const BSONObj& cmdObj,
                      BSONObjBuilder& result) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return appendCommandStatus(result, SessionsCommandFCV34Status(getName()));
         }
 
diff --git a/src/mongo/db/commands/kill_all_sessions_command.cpp b/src/mongo/db/commands/kill_all_sessions_command.cpp
index aeeffacc732..452a25cc6b5 100644
--- a/src/mongo/db/commands/kill_all_sessions_command.cpp
+++ b/src/mongo/db/commands/kill_all_sessions_command.cpp
@@ -73,8 +73,7 @@ public:
                                  const std::string& dbname,
                                  const BSONObj& cmdObj) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return SessionsCommandFCV34Status(getName());
         }
 
@@ -92,8 +91,7 @@ public:
                      const BSONObj& cmdObj,
                      BSONObjBuilder& result) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return appendCommandStatus(result, SessionsCommandFCV34Status(getName()));
         }
 
diff --git a/src/mongo/db/commands/kill_sessions_command.cpp b/src/mongo/db/commands/kill_sessions_command.cpp
index c8b67f8f695..9e6c9e05dc1 100644
--- a/src/mongo/db/commands/kill_sessions_command.cpp
+++ b/src/mongo/db/commands/kill_sessions_command.cpp
@@ -102,8 +102,7 @@ public:
                                  const std::string& dbname,
                                  const BSONObj& cmdObj) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return SessionsCommandFCV34Status(getName());
         }
 
@@ -115,8 +114,7 @@ public:
                      const BSONObj& cmdObj,
                      BSONObjBuilder& result) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return appendCommandStatus(result, SessionsCommandFCV34Status(getName()));
         }
 
diff --git a/src/mongo/db/commands/mr.cpp b/src/mongo/db/commands/mr.cpp
index 27f907f4ab8..f8882ec158f 100644
--- a/src/mongo/db/commands/mr.cpp
+++ b/src/mongo/db/commands/mr.cpp
@@ -1738,8 +1738,7 @@ public:
         Config config(dbname, cmdObj.firstElement().embeddedObjectUserCheck());
 
         if (cmdObj["finalOutputCollIsSharded"].trueValue() &&
-            serverGlobalParams.featureCompatibility.version.load() >=
-                ServerGlobalParams::FeatureCompatibility::Version::k36) {
+            serverGlobalParams.featureCompatibility.isSchemaVersion36()) {
             uassert(ErrorCodes::InvalidOptions,
                     "This shard has feature compatibility version 3.6, so it expects mongos to "
                     "send the UUID to use for the sharded output collection. Was the mapReduce "
diff --git a/src/mongo/db/commands/refresh_logical_session_cache_now.cpp b/src/mongo/db/commands/refresh_logical_session_cache_now.cpp
index cb607f13b82..cf4d6a713c4 100644
--- a/src/mongo/db/commands/refresh_logical_session_cache_now.cpp
+++ b/src/mongo/db/commands/refresh_logical_session_cache_now.cpp
@@ -66,8 +66,7 @@ public:
                                  const std::string& dbname,
                                  const BSONObj& cmdObj) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return SessionsCommandFCV34Status(getName());
         }
 
@@ -79,8 +78,7 @@ public:
                      const BSONObj& cmdObj,
                      BSONObjBuilder& result) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return appendCommandStatus(result, SessionsCommandFCV34Status(getName()));
         }
 
diff --git a/src/mongo/db/commands/refresh_sessions_command.cpp b/src/mongo/db/commands/refresh_sessions_command.cpp
index 452894bd24f..c8dc0b31914 100644
--- a/src/mongo/db/commands/refresh_sessions_command.cpp
+++ b/src/mongo/db/commands/refresh_sessions_command.cpp
@@ -62,8 +62,7 @@ public:
                                  const std::string& dbname,
                                  const BSONObj& cmdObj) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return SessionsCommandFCV34Status(getName());
         }
 
@@ -84,8 +83,7 @@ public:
                      const BSONObj& cmdObj,
                      BSONObjBuilder& result) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return appendCommandStatus(result, SessionsCommandFCV34Status(getName()));
         }
 
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 92d8ce3e0e3..da5b4876311 100644
--- a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
+++ b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
@@ -102,10 +102,8 @@ public:
     }
 
     bool isFCVUpgrade(StringData version) {
-        const auto existingVersion = FeatureCompatibilityVersion::toString(
-            serverGlobalParams.featureCompatibility.version.load());
         return version == FeatureCompatibilityVersionCommandParser::kVersion36 &&
-            existingVersion == FeatureCompatibilityVersionCommandParser::kVersion34;
+            !serverGlobalParams.featureCompatibility.isFullyUpgradedTo36();
     }
 
 
@@ -116,7 +114,7 @@ public:
         const auto version = uassertStatusOK(
             FeatureCompatibilityVersionCommandParser::extractVersionFromCommand(getName(), cmdObj));
         auto existingVersion = FeatureCompatibilityVersion::toString(
-                                   serverGlobalParams.featureCompatibility.version.load())
+                                   serverGlobalParams.featureCompatibility.getVersion())
                                    .toString();
 
         // Wait for majority commit in case we're upgrading simultaneously with another session.
diff --git a/src/mongo/db/commands/start_session_command.cpp b/src/mongo/db/commands/start_session_command.cpp
index 05341a93c2f..6454bc2dc50 100644
--- a/src/mongo/db/commands/start_session_command.cpp
+++ b/src/mongo/db/commands/start_session_command.cpp
@@ -67,8 +67,7 @@ public:
                                  const std::string& dbname,
                                  const BSONObj& cmdObj) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return SessionsCommandFCV34Status(getName());
         }
 
@@ -80,8 +79,7 @@ public:
                      const BSONObj& cmdObj,
                      BSONObjBuilder& result) override {
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             return appendCommandStatus(result, SessionsCommandFCV34Status(getName()));
         }
 
diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp
index 33616432f3b..d3bc602d95e 100644
--- a/src/mongo/db/db.cpp
+++ b/src/mongo/db/db.cpp
@@ -411,8 +411,8 @@ void repairDatabasesAndCheckVersion(OperationContext* opCtx) {
                         fassertFailedNoTrace(40283);
                     }
                     auto versionInfo = swVersionInfo.getValue();
-                    serverGlobalParams.featureCompatibility.version.store(versionInfo.version);
-                    serverGlobalParams.featureCompatibility.targetVersion.store(
+                    serverGlobalParams.featureCompatibility.setVersion(versionInfo.version);
+                    serverGlobalParams.featureCompatibility.setTargetVersion(
                         versionInfo.targetVersion);
 
                     // On startup, if the targetVersion field exists, then an upgrade/downgrade
@@ -1050,8 +1050,7 @@ void shutdownTask() {
             opCtx = uniqueOpCtx.get();
         }
 
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             log(LogComponent::kReplication) << "shutdown: removing all drop-pending collections...";
             repl::DropPendingCollectionReaper::get(serviceContext)
                 ->dropCollectionsOlderThan(opCtx, repl::OpTime::max());
diff --git a/src/mongo/db/initialize_operation_session_info.cpp b/src/mongo/db/initialize_operation_session_info.cpp
index eeaa6aca278..a3ca5b66eb1 100644
--- a/src/mongo/db/initialize_operation_session_info.cpp
+++ b/src/mongo/db/initialize_operation_session_info.cpp
@@ -46,8 +46,7 @@ void initializeOperationSessionInfo(OperationContext* opCtx,
         return;
     }
 
-    if (serverGlobalParams.featureCompatibility.version.load() ==
-        ServerGlobalParams::FeatureCompatibility::Version::k34) {
+    if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         return;
     }
 
diff --git a/src/mongo/db/keys_collection_cache_reader_and_updater.cpp b/src/mongo/db/keys_collection_cache_reader_and_updater.cpp
index ce20c5d5993..65efb639e6b 100644
--- a/src/mongo/db/keys_collection_cache_reader_and_updater.cpp
+++ b/src/mongo/db/keys_collection_cache_reader_and_updater.cpp
@@ -83,8 +83,7 @@ StatusWith<KeysCollectionDocument> KeysCollectionCacheReaderAndUpdater::refresh(
         return {ErrorCodes::FailPointEnabled, "key generation disabled"};
     }
 
-    if (serverGlobalParams.featureCompatibility.version.load() ==
-        ServerGlobalParams::FeatureCompatibility::Version::k34) {
+    if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         return KeysCollectionCacheReader::refresh(opCtx);
     }
 
diff --git a/src/mongo/db/keys_collection_cache_reader_and_updater_test.cpp b/src/mongo/db/keys_collection_cache_reader_and_updater_test.cpp
index 75cf3d993e2..0010f262705 100644
--- a/src/mongo/db/keys_collection_cache_reader_and_updater_test.cpp
+++ b/src/mongo/db/keys_collection_cache_reader_and_updater_test.cpp
@@ -54,7 +54,7 @@ protected:
     void setUp() override {
         ConfigServerTestFixture::setUp();
 
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k36);
         serverGlobalParams.featureCompatibility.validateFeaturesAsMaster.store(true);
 
@@ -457,7 +457,7 @@ TEST_F(CacheUpdaterTest, ShouldNotCreateKeysWithDisableKeyGenerationFailPoint) {
 }
 
 TEST_F(CacheUpdaterTest, ShouldNotCreateNewKeysInFeatureCompatiblityVersion34) {
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k34);
 
     KeysCollectionCacheReaderAndUpdater updater("dummy", catalogClient(), Seconds(5));
@@ -474,7 +474,7 @@ TEST_F(CacheUpdaterTest, ShouldNotCreateNewKeysInFeatureCompatiblityVersion34) {
     }
 
     // Increase the feature compatibility version and verify keys are found after refresh.
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k36);
 
     {
diff --git a/src/mongo/db/keys_collection_manager_sharding.cpp b/src/mongo/db/keys_collection_manager_sharding.cpp
index c63aa33e1eb..265dbf9e51f 100644
--- a/src/mongo/db/keys_collection_manager_sharding.cpp
+++ b/src/mongo/db/keys_collection_manager_sharding.cpp
@@ -236,8 +236,7 @@ void KeysCollectionManagerSharding::PeriodicRunner::_doPeriodicRefresh(
         Milliseconds nextWakeup = kRefreshIntervalIfErrored;
 
         // No need to refresh keys in FCV 3.4, since key generation will be disabled.
-        if (serverGlobalParams.featureCompatibility.version.load() !=
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             auto latestKeyStatusWith = (*doRefresh)(opCtx.get());
             if (latestKeyStatusWith.getStatus().isOK()) {
                 errorCount = 0;
diff --git a/src/mongo/db/keys_collection_manager_sharding_test.cpp b/src/mongo/db/keys_collection_manager_sharding_test.cpp
index 4c209a87e62..27e659c38a4 100644
--- a/src/mongo/db/keys_collection_manager_sharding_test.cpp
+++ b/src/mongo/db/keys_collection_manager_sharding_test.cpp
@@ -59,7 +59,7 @@ protected:
     void setUp() override {
         ConfigServerTestFixture::setUp();
 
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k36);
         serverGlobalParams.featureCompatibility.validateFeaturesAsMaster.store(true);
 
@@ -375,7 +375,7 @@ TEST_F(KeysManagerShardedTest, HasSeenKeysIsFalseUntilKeysAreFound) {
 }
 
 TEST_F(KeysManagerShardedTest, ShouldNotReturnKeysInFeatureCompatibilityVersion34) {
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k34);
 
     keyManager()->startMonitoring(getServiceContext());
diff --git a/src/mongo/db/logical_session_id_test.cpp b/src/mongo/db/logical_session_id_test.cpp
index 6d796fb7710..9e9e828372b 100644
--- a/src/mongo/db/logical_session_id_test.cpp
+++ b/src/mongo/db/logical_session_id_test.cpp
@@ -70,7 +70,7 @@ public:
     AuthorizationSessionForTest* authzSession;
 
     void setUp() {
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k36);
         session = transportLayer.createSession();
         client = serviceContext.makeClient("testClient", session);
diff --git a/src/mongo/db/logical_time_metadata_hook.cpp b/src/mongo/db/logical_time_metadata_hook.cpp
index 4a8d94241d6..12745e8d793 100644
--- a/src/mongo/db/logical_time_metadata_hook.cpp
+++ b/src/mongo/db/logical_time_metadata_hook.cpp
@@ -75,8 +75,7 @@ Status LogicalTimeMetadataHook::readReplyMetadata(OperationContext* opCtx,
         return Status::OK();
     }
 
-    if (serverGlobalParams.featureCompatibility.version.load() ==
-        ServerGlobalParams::FeatureCompatibility::Version::k34) {
+    if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         return Status::OK();
     }
 
diff --git a/src/mongo/db/logical_time_validator_test.cpp b/src/mongo/db/logical_time_validator_test.cpp
index 2f029d272c9..3f1a9c0bc18 100644
--- a/src/mongo/db/logical_time_validator_test.cpp
+++ b/src/mongo/db/logical_time_validator_test.cpp
@@ -61,7 +61,7 @@ protected:
     void setUp() override {
         ConfigServerTestFixture::setUp();
 
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k36);
         serverGlobalParams.featureCompatibility.validateFeaturesAsMaster.store(true);
 
diff --git a/src/mongo/db/ops/parsed_update.cpp b/src/mongo/db/ops/parsed_update.cpp
index 108475f84be..7944a16a545 100644
--- a/src/mongo/db/ops/parsed_update.cpp
+++ b/src/mongo/db/ops/parsed_update.cpp
@@ -160,8 +160,7 @@ Status ParsedUpdate::parseUpdate() {
 
 Status ParsedUpdate::parseArrayFilters() {
     if (!_request->getArrayFilters().empty() &&
-        serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        !serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         return Status(ErrorCodes::InvalidOptions,
                       str::stream()
                           << "The featureCompatibilityVersion must be 3.6 to use arrayFilters. See "
diff --git a/src/mongo/db/pipeline/document_source_change_stream.cpp b/src/mongo/db/pipeline/document_source_change_stream.cpp
index e9b49de2c47..33f04885148 100644
--- a/src/mongo/db/pipeline/document_source_change_stream.cpp
+++ b/src/mongo/db/pipeline/document_source_change_stream.cpp
@@ -251,8 +251,7 @@ list<intrusive_ptr<DocumentSource>> DocumentSourceChangeStream::createFromBson(
             << "The featureCompatibilityVersion must be 3.6 to use the $changeStream stage. See "
             << feature_compatibility_version::kDochubLink
             << ".",
-        serverGlobalParams.featureCompatibility.version.load() !=
-            ServerGlobalParams::FeatureCompatibility::Version::k34);
+        serverGlobalParams.featureCompatibility.isFullyUpgradedTo36());
     // TODO: Add sharding support here (SERVER-29141).
     uassert(
         40470, "The $changeStream stage is not supported on sharded systems.", !expCtx->inMongos);
diff --git a/src/mongo/db/pipeline/document_source_change_stream_test.cpp b/src/mongo/db/pipeline/document_source_change_stream_test.cpp
index 989a331a1a4..9f5b1f5844e 100644
--- a/src/mongo/db/pipeline/document_source_change_stream_test.cpp
+++ b/src/mongo/db/pipeline/document_source_change_stream_test.cpp
@@ -72,11 +72,11 @@ class EnsureFCV {
 public:
     using Version = ServerGlobalParams::FeatureCompatibility::Version;
     EnsureFCV(Version version)
-        : _origVersion(serverGlobalParams.featureCompatibility.version.load()) {
-        serverGlobalParams.featureCompatibility.version.store(version);
+        : _origVersion(serverGlobalParams.featureCompatibility.getVersion()) {
+        serverGlobalParams.featureCompatibility.setVersion(version);
     }
     ~EnsureFCV() {
-        serverGlobalParams.featureCompatibility.version.store(_origVersion);
+        serverGlobalParams.featureCompatibility.setVersion(_origVersion);
     }
 
 private:
diff --git a/src/mongo/db/pipeline/pipeline_test.cpp b/src/mongo/db/pipeline/pipeline_test.cpp
index 8a29dd8b9e4..aa58c26bdfa 100644
--- a/src/mongo/db/pipeline/pipeline_test.cpp
+++ b/src/mongo/db/pipeline/pipeline_test.cpp
@@ -74,11 +74,11 @@ class EnsureFCV {
 public:
     using Version = ServerGlobalParams::FeatureCompatibility::Version;
     EnsureFCV(Version version)
-        : _origVersion(serverGlobalParams.featureCompatibility.version.load()) {
-        serverGlobalParams.featureCompatibility.version.store(version);
+        : _origVersion(serverGlobalParams.featureCompatibility.getVersion()) {
+        serverGlobalParams.featureCompatibility.setVersion(version);
     }
     ~EnsureFCV() {
-        serverGlobalParams.featureCompatibility.version.store(_origVersion);
+        serverGlobalParams.featureCompatibility.setVersion(_origVersion);
     }
 
 private:
diff --git a/src/mongo/db/read_concern.cpp b/src/mongo/db/read_concern.cpp
index 4b055c6f646..35d625ccf84 100644
--- a/src/mongo/db/read_concern.cpp
+++ b/src/mongo/db/read_concern.cpp
@@ -158,8 +158,7 @@ Status waitForReadConcern(OperationContext* opCtx, const repl::ReadConcernArgs&
 
     auto afterClusterTime = readConcernArgs.getArgsClusterTime();
     if (afterClusterTime) {
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-                ServerGlobalParams::FeatureCompatibility::Version::k34 &&
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36() &&
             ShardingState::get(opCtx)->enabled()) {
             return {ErrorCodes::InvalidOptions,
                     "readConcern afterClusterTime is not available in featureCompatibilityVersion "
diff --git a/src/mongo/db/repl/bgsync.cpp b/src/mongo/db/repl/bgsync.cpp
index 21c88b4f6d3..447d0949d7a 100644
--- a/src/mongo/db/repl/bgsync.cpp
+++ b/src/mongo/db/repl/bgsync.cpp
@@ -679,8 +679,7 @@ void BackgroundSync::_runRollback(OperationContext* opCtx,
             opCtx, source, &localOplog, storageInterface, getConnection);
 
     } else if (rollbackMethod != kRollbackViaRefetchNoUUID &&
-               (serverGlobalParams.featureCompatibility.version.load() ==
-                ServerGlobalParams::FeatureCompatibility::Version::k36)) {
+               (serverGlobalParams.featureCompatibility.isFullyUpgradedTo36())) {
         // If the user is in FCV 3.6 and the user did not specify to fall back on "roll back via
         // refetch" without UUID support, then we use "roll back via refetch" with UUIDs.
 
@@ -698,14 +697,12 @@ void BackgroundSync::_runRollback(OperationContext* opCtx,
     } else {
         if (rollbackMethod == kRollbackToCheckpoint) {
             invariant(!supportsCheckpointRollback);
-            invariant(serverGlobalParams.featureCompatibility.version.load() ==
-                      ServerGlobalParams::FeatureCompatibility::Version::k34);
+            invariant(!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36());
             log() << "Rollback using the 'rollbackViaRefetchNoUUID' method because this storage "
                      "engine does not support 'roll back to a checkpoint' and we are "
                      "in featureCompatibilityVersion 3.4.";
         } else if (rollbackMethod == kRollbackViaRefetch) {
-            invariant(serverGlobalParams.featureCompatibility.version.load() ==
-                      ServerGlobalParams::FeatureCompatibility::Version::k34);
+            invariant(!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36());
             log() << "Rollback using the 'rollbackViaRefetchNoUUID' method. 'rollbackViaRefetch' "
                      "with UUID support is not feature compatible with featureCompatabilityVersion "
                      "3.4.";
diff --git a/src/mongo/db/repl/idempotency_test.cpp b/src/mongo/db/repl/idempotency_test.cpp
index 84a03172947..b6d44eff367 100644
--- a/src/mongo/db/repl/idempotency_test.cpp
+++ b/src/mongo/db/repl/idempotency_test.cpp
@@ -193,13 +193,13 @@ void RandomizedIdempotencyTest::runIdempotencyTestCase() {
 }
 
 TEST_F(RandomizedIdempotencyTest, CheckUpdateSequencesAreIdempotentWhenFCV34) {
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k34);
     runIdempotencyTestCase();
 }
 
 TEST_F(RandomizedIdempotencyTest, CheckUpdateSequencesAreIdempotentWhenFCV36) {
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k36);
     runIdempotencyTestCase();
 }
diff --git a/src/mongo/db/repl/oplog.cpp b/src/mongo/db/repl/oplog.cpp
index 99d2e0c3929..110909ffd6c 100644
--- a/src/mongo/db/repl/oplog.cpp
+++ b/src/mongo/db/repl/oplog.cpp
@@ -344,9 +344,7 @@ OplogDocWriter _logOpWriter(OperationContext* opCtx,
     if (o2)
         b.append("o2", *o2);
 
-    if (wallTime != Date_t{} &&
-        serverGlobalParams.featureCompatibility.version.load() !=
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+    if (wallTime != Date_t{} && serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         b.appendDate("wall", wallTime);
     }
 
diff --git a/src/mongo/db/repl/oplog_fetcher.cpp b/src/mongo/db/repl/oplog_fetcher.cpp
index b4b0b024e4f..12cc813de49 100644
--- a/src/mongo/db/repl/oplog_fetcher.cpp
+++ b/src/mongo/db/repl/oplog_fetcher.cpp
@@ -367,8 +367,7 @@ BSONObj OplogFetcher::_makeFindCommandObject(const NamespaceString& nss,
     // TODO(SERVER-30977): Remove the term comparison when this ticket is fixed.
     if (term == lastOpTimeFetched.getTerm()) {
         cmdBob.append("readConcern",
-                      serverGlobalParams.featureCompatibility.version.load() ==
-                              ServerGlobalParams::FeatureCompatibility::Version::k34
+                      !serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()
                           ? BSON("afterOpTime" << lastOpTimeFetched)
                           : BSON("afterClusterTime" << lastOpTimeFetched.getTimestamp()));
     }
diff --git a/src/mongo/db/repl/oplog_fetcher_test.cpp b/src/mongo/db/repl/oplog_fetcher_test.cpp
index c87542c9e12..b2195e50710 100644
--- a/src/mongo/db/repl/oplog_fetcher_test.cpp
+++ b/src/mongo/db/repl/oplog_fetcher_test.cpp
@@ -269,11 +269,11 @@ class EnsureFCV {
 public:
     using Version = ServerGlobalParams::FeatureCompatibility::Version;
     EnsureFCV(Version version)
-        : _version(version), _origVersion(serverGlobalParams.featureCompatibility.version.load()) {
-        serverGlobalParams.featureCompatibility.version.store(_version);
+        : _version(version), _origVersion(serverGlobalParams.featureCompatibility.getVersion()) {
+        serverGlobalParams.featureCompatibility.setVersion(_version);
     }
     ~EnsureFCV() {
-        serverGlobalParams.featureCompatibility.version.store(_origVersion);
+        serverGlobalParams.featureCompatibility.setVersion(_origVersion);
     }
 
 private:
@@ -297,8 +297,7 @@ TEST_F(OplogFetcherTest, FindQueryHasNoReadconcernIfTermUninitialized) {
 
 TEST_F(OplogFetcherTest, FindQueryHasAfterOpTimeWithFeatureCompatibilityVersion34) {
     EnsureFCV ensureFCV(EnsureFCV::Version::k34);
-    ASSERT(serverGlobalParams.featureCompatibility.version.load() ==
-           ServerGlobalParams::FeatureCompatibility::Version::k34);
+    ASSERT(!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36());
     auto cmdObj = makeOplogFetcher(_createConfig(true))->getFindQuery_forTest();
     auto readConcernElem = cmdObj["readConcern"];
     ASSERT_EQUALS(mongo::BSONType::Object, readConcernElem.type());
@@ -310,8 +309,7 @@ TEST_F(OplogFetcherTest, FindQueryHasAfterOpTimeWithFeatureCompatibilityVersion3
 
 TEST_F(OplogFetcherTest, FindQueryHasAfterOpTimeWithFeatureCompatibilityVersion36) {
     EnsureFCV ensureFCV(EnsureFCV::Version::k36);
-    ASSERT(serverGlobalParams.featureCompatibility.version.load() !=
-           ServerGlobalParams::FeatureCompatibility::Version::k34);
+    ASSERT(serverGlobalParams.featureCompatibility.isFullyUpgradedTo36());
     auto cmdObj = makeOplogFetcher(_createConfig(true))->getFindQuery_forTest();
     auto readConcernElem = cmdObj["readConcern"];
     ASSERT_EQUALS(mongo::BSONType::Object, readConcernElem.type());
diff --git a/src/mongo/db/repl/replication_consistency_markers_impl.cpp b/src/mongo/db/repl/replication_consistency_markers_impl.cpp
index c4be7496074..39fc82c321b 100644
--- a/src/mongo/db/repl/replication_consistency_markers_impl.cpp
+++ b/src/mongo/db/repl/replication_consistency_markers_impl.cpp
@@ -277,8 +277,7 @@ Timestamp ReplicationConsistencyMarkersImpl::getOplogTruncateAfterPoint(
     OperationContext* opCtx) const {
     auto doc = _getOplogTruncateAfterPointDocument(opCtx);
     if (!doc) {
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k34) {
+        if (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             LOG(3) << "Falling back on old oplog delete from point because there is no oplog "
                       "truncate after point and we are in FCV 3.4.";
             return _getOldOplogDeleteFromPoint(opCtx);
diff --git a/src/mongo/db/repl/replication_consistency_markers_impl_test.cpp b/src/mongo/db/repl/replication_consistency_markers_impl_test.cpp
index bb3199e2a62..105613c516f 100644
--- a/src/mongo/db/repl/replication_consistency_markers_impl_test.cpp
+++ b/src/mongo/db/repl/replication_consistency_markers_impl_test.cpp
@@ -316,7 +316,7 @@ TEST_F(ReplicationConsistencyMarkersTest, OplogTruncateAfterPointUpgrade) {
     consistencyMarkers.initializeMinValidDocument(opCtx);
 
     // Set the feature compatibility version to 3.6.
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k36);
 
     // Check that we see no oplog truncate after point in FCV 3.6.
@@ -324,7 +324,7 @@ TEST_F(ReplicationConsistencyMarkersTest, OplogTruncateAfterPointUpgrade) {
     ASSERT_EQ(consistencyMarkers.getMinValid(opCtx), minValidTime);
 
     // Set the feature compatibility version to 3.4.
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k34);
 
     // Check that we see the old oplog delete from point in FCV 3.4.
@@ -347,7 +347,7 @@ TEST_F(ReplicationConsistencyMarkersTest, OplogTruncateAfterPointUpgrade) {
     ASSERT_EQ(consistencyMarkers.getMinValid(opCtx), minValidTime);
 
     // Set the feature compatibility version to 3.6.
-    serverGlobalParams.featureCompatibility.version.store(
+    serverGlobalParams.featureCompatibility.setVersion(
         ServerGlobalParams::FeatureCompatibility::Version::k36);
 
     // Check that after removing the old oplog delete from point, that we do not see the oplog
diff --git a/src/mongo/db/repl/replication_info.cpp b/src/mongo/db/repl/replication_info.cpp
index e29d748aa37..f27e1608e73 100644
--- a/src/mongo/db/repl/replication_info.cpp
+++ b/src/mongo/db/repl/replication_info.cpp
@@ -363,7 +363,7 @@ public:
         // Then if the connection is from a mongod/mongos of an earlier version, it will fail to
         // connect.
         if (internalClientElement &&
-            serverGlobalParams.featureCompatibility.version.load() ==
+            serverGlobalParams.featureCompatibility.getVersion() ==
                 ServerGlobalParams::FeatureCompatibility::Version::k36) {
             result.append("minWireVersion", WireSpec::instance().incoming.maxWireVersion);
         } else {
diff --git a/src/mongo/db/s/config/configsvr_shard_collection_command.cpp b/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
index 3f95d89b31e..dbe4c7c2a36 100644
--- a/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
+++ b/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
@@ -640,8 +640,7 @@ void migrateAndFurtherSplitInitialChunks(OperationContext* opCtx,
 boost::optional<UUID> getUUIDFromPrimaryShard(const NamespaceString& nss,
                                               ScopedDbConnection& conn) {
     // UUIDs were introduced in featureCompatibilityVersion 3.6.
-    if (serverGlobalParams.featureCompatibility.version.load() <
-        ServerGlobalParams::FeatureCompatibility::Version::k36) {
+    if (!serverGlobalParams.featureCompatibility.isSchemaVersion36()) {
         return boost::none;
     }
 
diff --git a/src/mongo/db/s/migration_destination_manager.cpp b/src/mongo/db/s/migration_destination_manager.cpp
index 86688ba08ca..0dd4967c9f5 100644
--- a/src/mongo/db/s/migration_destination_manager.cpp
+++ b/src/mongo/db/s/migration_destination_manager.cpp
@@ -550,10 +550,7 @@ void MigrationDestinationManager::_migrateDriver(OperationContext* opCtx,
                 info = entry["info"].Obj();
             }
 
-            // If in featureCompatibilityVersion >= 3.6, require the donor to return the
-            // collection's UUID.
-            if (serverGlobalParams.featureCompatibility.version.load() >=
-                ServerGlobalParams::FeatureCompatibility::Version::k36) {
+            if (serverGlobalParams.featureCompatibility.isSchemaVersion36()) {
                 if (info["uuid"].eoo()) {
                     setStateFailWarn(str::stream()
                                      << "The donor shard did not return a UUID for collection "
diff --git a/src/mongo/db/s/migration_source_manager.cpp b/src/mongo/db/s/migration_source_manager.cpp
index e16addcd83e..d1ed1b7be88 100644
--- a/src/mongo/db/s/migration_source_manager.cpp
+++ b/src/mongo/db/s/migration_source_manager.cpp
@@ -230,8 +230,7 @@ Status MigrationSourceManager::enterCriticalSection(OperationContext* opCtx) {
 
     const ShardId& recipientId = _args.getToShardId();
     if (!_collectionMetadata->getChunkManager()->getVersion(recipientId).isSet() &&
-        serverGlobalParams.featureCompatibility.version.load() >=
-            ServerGlobalParams::FeatureCompatibility::Version::k36) {
+        serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         // The recipient didn't have any chunks of this collection. Write the no-op message so that
         // change stream will notice that and close cursor to notify mongos to target to the new
         // shard.
diff --git a/src/mongo/db/s/session_catalog_migration_destination_test.cpp b/src/mongo/db/s/session_catalog_migration_destination_test.cpp
index 3dc34514061..56a63df7afb 100644
--- a/src/mongo/db/s/session_catalog_migration_destination_test.cpp
+++ b/src/mongo/db/s/session_catalog_migration_destination_test.cpp
@@ -83,7 +83,7 @@ repl::OplogEntry extractInnerOplog(const repl::OplogEntry& oplog) {
 class SessionCatalogMigrationDestinationTest : public ShardingMongodTestFixture {
 public:
     void setUp() override {
-        serverGlobalParams.featureCompatibility.version.store(
+        serverGlobalParams.featureCompatibility.setVersion(
             ServerGlobalParams::FeatureCompatibility::Version::k36);
         serverGlobalParams.clusterRole = ClusterRole::ShardServer;
         ShardingMongodTestFixture::setUp();
diff --git a/src/mongo/db/server_options.h b/src/mongo/db/server_options.h
index 76b2df4aa6c..c3cd1b89b8d 100644
--- a/src/mongo/db/server_options.h
+++ b/src/mongo/db/server_options.h
@@ -167,25 +167,36 @@ struct ServerGlobalParams {
          */
         enum class Version { k34, k36, kUnset };
 
-        AtomicWord<Version> version{Version::k34};
+        const Version getVersion() const {
+            return _version.load();
+        }
 
-        // If set, an upgrade or downgrade is in progress to the set version.
-        AtomicWord<Version> targetVersion{Version::kUnset};
+        void setVersion(Version version) {
+            return _version.store(version);
+        }
+
+        const Version getTargetVersion() const {
+            return _targetVersion.load();
+        }
+
+        void setTargetVersion(Version version) {
+            return _targetVersion.store(version);
+        }
 
         const bool isFullyUpgradedTo36() {
-            return (version.load() == Version::k36 && targetVersion.load() == Version::kUnset);
+            return (_version.load() == Version::k36 && _targetVersion.load() == Version::kUnset);
         }
 
         const bool isUpgradingTo36() {
-            return (version.load() == Version::k34 && targetVersion.load() == Version::k36);
+            return (_version.load() == Version::k34 && _targetVersion.load() == Version::k36);
         }
 
         const bool isFullyDowngradedTo34() {
-            return (version.load() == Version::k34 && targetVersion.load() == Version::kUnset);
+            return (_version.load() == Version::k34 && _targetVersion.load() == Version::kUnset);
         }
 
         const bool isDowngradingTo34() {
-            return (version.load() == Version::k34 && targetVersion.load() == Version::k34);
+            return (_version.load() == Version::k34 && _targetVersion.load() == Version::k34);
         }
 
         // This determines whether to give Collections UUIDs upon creation.
@@ -199,6 +210,13 @@ struct ServerGlobalParams {
         // a master) always validates in "3.4" mode so that it can sync 3.4 features, even when in
         // "3.2" feature compatibility mode.
         AtomicWord<bool> validateFeaturesAsMaster{true};
+
+    private:
+        AtomicWord<Version> _version{Version::k34};
+
+        // If set, an upgrade or downgrade is in progress to the set version.
+        AtomicWord<Version> _targetVersion{Version::kUnset};
+
     } featureCompatibility;
 
     std::vector<std::string> disabledSecureAllocatorDomains;
diff --git a/src/mongo/db/service_entry_point_mongod.cpp b/src/mongo/db/service_entry_point_mongod.cpp
index d4a45dd7a80..d0c2e449646 100644
--- a/src/mongo/db/service_entry_point_mongod.cpp
+++ b/src/mongo/db/service_entry_point_mongod.cpp
@@ -272,8 +272,7 @@ void appendReplyMetadata(OperationContext* opCtx,
                 .writeToMetadata(metadataBob)
                 .transitional_ignore();
         }
-        if (serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k36) {
+        if (serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             if (LogicalTimeValidator::isAuthorizedToAdvanceClock(opCtx)) {
                 // No need to sign cluster times for internal clients.
                 SignedLogicalTime currentTime(
@@ -500,8 +499,7 @@ bool runCommandImpl(OperationContext* opCtx,
     // An uninitialized operation time means the cluster time is not propagated, so the operation
     // time should not be attached to the response.
     if (operationTime != LogicalTime::kUninitialized &&
-        serverGlobalParams.featureCompatibility.version.load() ==
-            ServerGlobalParams::FeatureCompatibility::Version::k36) {
+        serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
         operationTime.appendAsOperationTime(&inPlaceReplyBob);
     }
 
@@ -679,8 +677,7 @@ void execCommandDatabase(OperationContext* opCtx,
         if (!opCtx->getClient()->isInDirectClient() &&
             readConcernArgs.getLevel() != repl::ReadConcernLevel::kAvailableReadConcern &&
             (iAmPrimary ||
-             (serverGlobalParams.featureCompatibility.version.load() ==
-                  ServerGlobalParams::FeatureCompatibility::Version::k36 &&
+             (serverGlobalParams.featureCompatibility.isFullyUpgradedTo36() &&
               (readConcernArgs.hasLevel() || readConcernArgs.getArgsClusterTime())))) {
             oss.initializeShardVersion(NamespaceString(command->parseNs(dbname, request.body)),
                                        shardVersionFieldIdx);
@@ -748,8 +745,7 @@ void execCommandDatabase(OperationContext* opCtx,
         // An uninitialized operation time means the cluster time is not propagated, so the
         // operation time should not be attached to the error response.
         if (operationTime != LogicalTime::kUninitialized &&
-            serverGlobalParams.featureCompatibility.version.load() ==
-                ServerGlobalParams::FeatureCompatibility::Version::k36) {
+            serverGlobalParams.featureCompatibility.isFullyUpgradedTo36()) {
             LOG(1) << "assertion while executing command '" << request.getCommandName() << "' "
                    << "on database '" << request.getDatabase() << "' "
                    << "with arguments '" << command->getRedactedCopyForLogging(request.body)
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
index 334ba3852bc..a43c9cb9f49 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
@@ -495,9 +495,8 @@ void WiredTigerKVEngine::cleanShutdown() {
             closeConfig = "leak_memory=true";
         }
 
-        const bool needsDowngrade = !_readOnly &&
-            serverGlobalParams.featureCompatibility.version.load() ==
-                ServerGlobalParams::FeatureCompatibility::Version::k34;
+        const bool needsDowngrade =
+            !_readOnly && !serverGlobalParams.featureCompatibility.isFullyUpgradedTo36();
 
         invariantWTOK(_conn->close(_conn, closeConfig));
         _conn = nullptr;
diff --git a/src/mongo/db/update/update_driver.cpp b/src/mongo/db/update/update_driver.cpp
index 5380de021ae..fb076acf98d 100644
--- a/src/mongo/db/update/update_driver.cpp
+++ b/src/mongo/db/update/update_driver.cpp
@@ -198,8 +198,7 @@ Status UpdateDriver::parse(
     } else if (_modOptions.fromOplogApplication) {
         updateSemantics = UpdateSemantics::kModifierInterface;
     } else {
-        updateSemantics = (serverGlobalParams.featureCompatibility.version.load() ==
-                           ServerGlobalParams::FeatureCompatibility::Version::k34)
+        updateSemantics = (!serverGlobalParams.featureCompatibility.isFullyUpgradedTo36())
             ? UpdateSemantics::kModifierInterface
             : UpdateSemantics::kUpdateNode;
     }