Hi,
It has a feature of Third party software removal.
System Change Exception (DNS)
Resetpass.batch file is removed from tools folder.
Third party software upgrades
Also The Latest Version of SEP 12.1.1101.401 (RU1 MP1) has -
• Browser Intrusion Prevention in the Intrusion Prevention Policy is compatible with Firefox 9 and Firefox 10.
• The Quarantine Server is compatible with 64 bit operating Systems.
• Remote Monitoring and Management (RMM) Support
• Release of the Symantec Endpoint Protection Management Plug-in 1.5 for Kaseya
• Changes to Tamper Protection alerts and logging
https://www-secure.symantec.com/connect/forums/tam...
Go through following article to know the differences in details.
https://www-secure.symantec.com/connect/articles/what-s-new-sep-121-ru1-mp1