Starting on May 12th, Microsoft will begin a verification of some update scenarios on Windows 7 RC (build 7100) (download), similar to the update verification did for Windows 7 Beta (build 7000) to verify the update infrastructure to ensure that real updates process will run smoothly. There will be at most 10 updates, and as before, they will not deliver any new features or fixes. Many of the updates will install automatically, and a few will not. Users will need to go to the Windows Update control panel and manually start installation of the updates that don’t install automatically, and the updates will be clearly marked as test updates.
More info: Microsoft