[Doc]: Fix RN 9.6.4.1

Author: dmpgpro

doc/src/sgml/release-pro-9.6.sgml

@@ -29,10 +29,11 @@
         use of <xref linkend="pgupgrade">, is required for those
         wishing to migrate data from any previous major release.
     </para>
-    <para>A dump/restore is not required for those running 9.6.3.3.</para>
-    <para>However, if you are upgrading from vanilla PostgreSQL 9.6.x, some
-      catalog changes should be applied.
-    </para>
+    <para>A dump/restore is required for those running 9.6.3.3, because
+      catalog number format has been changed for better <productname>Postgres Pro</productname>
+      identification.</para>
+    <para>If you are upgrading from vanilla PostgreSQL 9.6.x, some
+      catalog changes should be applied.</para>    
     <para>If you use binary packages, and your database is in the default
       location, this upgrade should be performed automatically. If you've
       compiled Postgres Pro from source or create your database in a