DOCSP-29181 mongosync documentation update (#289)

* DOCSP-29181 mongosync documentation update

* DOCSP-29181 updates for copy feedback

* DOCSP-29181 updates for feedback

* Update source/reference/mongosync.txt

Co-authored-by: Evgeni Dobranov <[email protected]>

---------

Co-authored-by: Evgeni Dobranov <[email protected]>

Author: kanchana-mongodb

source/reference/mongosync.txt

@@ -27,7 +27,15 @@ line options.
 .. note::
 
    - Both the source cluster and destination cluster must use MongoDB
-     6.0 or later.
+     6.0 or later. 
+     
+     You can migrate data on clusters (source) with versions of MongoDB
+     lower than 6.0 to an Atlas cluster (destination). Migration from clusters with
+     lower version requires additional preparation and configuration in
+     the clusters with the lower version. `Contact
+     <https://mongodb.com/contact>`__ your account team to inquire about 
+     Professional Services.  
+
    - ``mongosync`` supports replica sets and sharded clusters.
    - Standalone MongoDB instances are not supported. :ref:`Convert the
      standalone instance <server-replica-set-deploy-convert>` to a