Hello,

The Latest Version of SEP 12.1 RU2 is released in Nov 2012.

Check these Article below:

Latest Symantec Endpoint Protection Releases - SEP 12.1 RU2 and SEP 11.0 RU7 MP3

https://www-secure.symantec.com/connect/articles/latest-symantec-endpoint-protection-releases-sep-121-ru2-and-sep-110-ru7-mp3

Latest Symantec Endpoint Protection Released - Symantec Endpoint Protection SBE 12.1. RU2

https://www-secure.symantec.com/connect/forums/latest-symantec-endpoint-protection-released-symantec-endpoint-protection-sbe-121-ru2

What are the Symantec Endpoint Protection (SEP) versions released officially?

https://www-secure.symantec.com/connect/articles/what-are-symantec-endpoint-protection-sep-versions-released-officially

In case you have an older version and If you are planning to upgrade or migrate to Symantec Endpoint Protection 12.1.2, please take a look at the latest how-to article - 

Best practices for upgrading to Symantec Endpoint Protection 12.1.2

http://www.symantec.com/business/support/index?page=content&id=TECH163700

Hope that helps!!