IronPort has a planned maintenance window on Friday, December 29th from 10PM to midnight. Your filters will still work; however, you may see a few timeouts to SBRS and AsyncOS. The box will reconnect frequenty so most systems will remain up-to-date throughout the window. There is no action required, just ignore the alerts during the window. If you have any specific questions contact IronPort directly:

Support Portal: http://www.ironport.com/support

Toll-Free Customer Support
United States: 1-877-641-4766