Windows 7 Beta Update Tests Begin February 24, 2009
As part of the regular beta testing cycle, the Windows 7 Engineering team will be releasing “test updates” to Windows Update. Users of beta build 7000 will receive notification of the “test update,” but it will not install automatically.
While these test updates will not contain any fixes or features, we encourage you to install the updates to help us test the serviceability of Windows 7.
Additional information can be found on the Microsoft Update Team Blog.