Adjust bwc version for max_concurrent_file_chunks

Relates #36981

server/src/main/java/org/elasticsearch/indices/recovery/RecoverySourceHandler.java

@@ -111,7 +111,7 @@ public class RecoverySourceHandler {
         this.logger = Loggers.getLogger(getClass(), request.shardId(), "recover to " + request.targetNode().getName());
         this.chunkSizeInBytes = fileChunkSizeInBytes;
         // if the target is on an old version, it won't be able to handle out-of-order file chunks.
-        this.maxConcurrentFileChunks = request.targetNode().getVersion().onOrAfter(Version.V_7_0_0) ? maxConcurrentFileChunks : 1;
+        this.maxConcurrentFileChunks = request.targetNode().getVersion().onOrAfter(Version.V_6_7_0) ? maxConcurrentFileChunks : 1;
     }
 
     public StartRecoveryRequest getRequest() {