Is there a list available?
Check this link:
Please click the "Mark as solution" link at bottom left on the post that best answers your question. This will benefit admins looking for a solution to the same problem.
SEP 12 RU2 is the new release which have new features and fixes that were in the earlier version.
Help Link: http://www.symantec.com/business/support/overview.jsp?pid=54619