Did you know you can hit the following links to see a complete history of Windows Client and Server monthly rollups by product version?
Check the In this release section for details on past and current updates on the given version.
After selecting an update, check the Improvements and fixes section for details on what’s included; quality improvements, security updates, etc.
The How to get this update section contains important information, including how the update is deployed (via Windows Update or other manual method).
TIP If you are not sure what version you or your customer is running click Start and run the Winver command.