Hello,
Here are the answers.
Is there any client only patch available for upgrading the clients from SEP RU6 MP2 to SEP 12.1 RU1?
Yes. Here are Links to the Patches.
Symantec Endpoint Protection 12.1 RU1 Client-only patch
http://www.symantec.com/docs/TECH174706
Also, check the same on https://fileconnect.symantec.com
Is it possible for migrating the SEPM from SEP RU7 to SEP 12.1 RU1?
Yes, It is possible.
Migration detects and migrates installations of the following Symantec legacy virus protection software:
• Symantec AntiVirus Corporate Edition 9.x and 10.x.
• Symantec Client Security 2.x and 3.x
• Symantec Endpoint Protection Small Business Edition 12.0
• Symantec Endpoint Protection 11.x *
• Symantec Sygate Enterprise Protection *
• Symantec AntiVirus for Mac *
* Legacy products marked with asterisk cannot be migrated to Small Business Edition. Also, you may migrate from a Small Business Edition to Enterprise version, but not the reverse.
NOTE: Migration of Symantec Endpoint Protection Manager 11 RU7 to 12.1 RTM is not supported. Migrations from 11.0 RU7 to 12.1 RU1 are supported. Migration of clients is supported in both versions.
Check these Articles -
Upgrading or migrating to Symantec Endpoint Protection 12.1
Planning for Migration to Symantec Endpoint Protection Manager 12.1
Hope that helps!!!