Hi,
Symantec will release the SONAR definition engine dated 09/05/2012, r. 11 as a throttled update, beginning September 13, 2012 and ending September 20, 2012. During the throttled update period, client computers that run LiveUpdate directly to the Symantec servers may receive content dated either 08/23/2012 r. 13 or 09/05/2012, r. 11.
Symantec Endpoint Protection 12.1.2 Beta clients and managers will receive definitions dated 08/31/2012 r. 11, with the same content as the 09/05/2012 r. 11 definitions. On September 20, 2012, Symantec will release a revision with the same content but a newer date to all update methods, including LiveUpdate, LiveUpdate Administrator, and Endpoint Protection Managers, so that all clients and managers will have the same content.
To know more about it, please check following article:
About the SONAR definitions release dated September 5, 2012, revision 11
http://www.symantec.com/docs/TECH196189
I hope it helps to everyone.