SEPM 11 RU7 MP2 to RU7 MP3 Upgrade Process Graphical Overview
This video demonstate upgrade process graphical overview from SEP 11 RU7 MP2 to RU7 MP3.
Prior to an upgrade please take the necessary backup.
Release Notes: http://www.symantec.com/docs/DOC6158
Refer this article as well:
Migrating to Symantec Endpoint Protection 11.0.7300 (RU7 MP3)