Hi,
Why don't you upgrade to the latest SEP version i.e. SEP 12.1 RU2?
Check till date SEP releases: http://bit.ly/m0vOJp
I believe upgrade to SEP 12.1 will be free of cost for all the existing SEP 11 customers.
Supported upgrade paths to Symantec Endpoint Protection Manager 12.1 from Symantec Endpoint Protection Manager 11.x
http://www.symantec.com/docs/TECH192779
Supported upgrade paths for the Symantec Endpoint Protection client
http://www.symantec.com/docs/HOWTO81070
However if you wish to upgrade to SEP 11 RU7 MP3 then go through the following articles.
Symantec™ Endpoint Protection and Symantec Network Access Control 11 Release Update 7 MP3 Release Notes
http://www.symantec.com/docs/DOC6158
Migrating to Symantec Endpoint Protection 11.0.7300 (RU7 MP3)
http://www.symantec.com/docs/TECH199189
Symantec Endpoint Protection 11.0.7300 (RU7 MP3) can migrate seamlessly over the following:
Symantec Endpoint Protection 11.0.7200 (RU7 MP2)
Symantec Endpoint Protection 11.0.7101 (RU7 MP1)
Symantec Endpoint Protection 11.0.7000 (RU7)
Supported Migration path SEP 11.x > SEP 11.0.7000.975 (RU7) > SEP 11.0.7300.1294 (RU7 MP3)