I run Zimbra 5.0.5 on Ubuntu 6.06 LTS server for 2 months now. Before, I received a lot of spam on various accounts. With the change to Zimbra, most of the spam now is filtered correctly. In the last 2-3 weeks however, I notice more spam not being filtered again.

I expect that there must be rules updates to reflect the latest virus patterns. Where can I check if these updates are done?