Microsoft released the Antigen 8 for SharePoint SP1 and Antigen 8 for IM SP1, and advises customers to upgrade to these service packs before AV engine mix changes on December 1st, 2009. The service packs can be downloaded from Microsoft Volume Licensing Service Center by opening “Servers” group and finding corresponding Forefront Server product. Antigen 8 for SharePoint SP1 (part number X16-09934) can be found under “Forefront Security for SharePoint with Service Pack 3”. Antigen 8 for IM SP1 (part number X16-09863) can be found under “Forefront Security for Office Communications Server”.