Hello,
Symantec Endpoint Protection 12.1.2 (RU2) can upgrade seamlessly over the following:
- Symantec Endpoint Protection 12.1.1101.401 (RU1 MP1)
- Symantec Endpoint Protection 12.1.1000.157 (RU1)
- Symantec Endpoint Protection 12.1.671.4971 (RTM)
- Symantec Endpoint Protection 11.x (can be upgraded to enterprise version only)
- Symantec Endpoint Protection Small Business Edition 12.0
Here are few Articles which you may refer while Upgrading to SEP 12.1 RU2
Best practices for upgrading to Symantec Endpoint Protection 12.1.2
http://www.symantec.com/docs/TECH163700
Upgrading or migrating to Symantec Endpoint Protection 12.1.2 (RU2)
http://www.symantec.com/docs/TECH197426
Hope that helps!!