1 files changed, 8 insertions, 1 deletions
diff --git a/src/mongo/db/repl/replication_info.cpp b/src/mongo/db/repl/replication_info.cpp
index d27257a8eb0..d655ccfa73b 100644
--- a/src/mongo/db/repl/replication_info.cpp
+++ b/src/mongo/db/repl/replication_info.cpp
@@ -279,7 +279,14 @@ public:
         appendReplicationInfo(txn, result, 0);
 
         if (serverGlobalParams.clusterRole == ClusterRole::ConfigServer) {
-            result.append("configsvr", 1);
+            // If we have feature compatibility version 3.4, use a config server mode that 3.2
+            // mongos won't understand. This should prevent a 3.2 mongos from joining the cluster or
+            // making a connection to the config servers.
+            int configServerModeNumber = (serverGlobalParams.featureCompatibility.version.load() ==
+                                          ServerGlobalParams::FeatureCompatibility::Version::k34)
+                ? 2
+                : 1;
+            result.append("configsvr", configServerModeNumber);
         }
 
         result.appendNumber("maxBsonObjectSize", BSONObjMaxUserSize);