We have a webpage to check the latest version of the Antivirus, IPS and PTP Definitions: http://www.symantec.com/security_response/definitions.jsp?pid=sep1213
it could be good to have also the information about the latest version of the definitions who don't update as frequently like:
AP Portal List
Centralized Reputation Settings
Submission Control signatures
Just for the customers to check that they are indeed uptodate with these definitions also
