From: New Antimalware Engine is planned for release on 15 July 2010 - Antimalware Engine Notifications - Site Home - TechNet Blogs (http://blogs.technet.com/b/enginenotifications/archive/2010/07/09/antimalware-engine-release-for-july-2010.aspx)
QuoteAs part of regular update of our Antimalware technology to address the latest in the threat landscape, the Microsoft Antimalware Team is planning to release a new antimalware engine on 15 July 2010.
Affected products: Microsoft Security Essentials (MSE), Forefront Client Security (FCS)
Engine Version will be in the range of 1.1.600X.0