DOC-2590-Added a NOTE on CRR upgrade [3.6]

Author: Tushar-TG-14

modules/installation/pages/upgrade.adoc

@@ -40,6 +40,11 @@ Call the xref:tigergraph-server:API:built-in-endpoints.adoc#_rebuild_graph_engin
 
 == Upgrading a CRR system
 
+[NOTE]
+====
+After upgrading to a newer version, you must perform a backup and restore on the newer version before enabling CRR, even if no data has changed. You cannot enable CRR using a backup from an earlier version.
+====
+
 To upgrade the TigerGraph software on a CRR system, follow this sequence of steps.
 
 . Disable CRR on your DR cluster.