Microsoft has released an update for WSUS on Windows 2012 and 2012 R2 server. This update is required to support deployment of the Windows 10 1511 upgrade by WSUS or the upcoming Configuration Manager (vNext).
Before installing this hotfix on Windows Server 2012 R2, verify that you already has this hotfix installed https://support.microsoft.com/en-us/kb/2919355
More information can be found here:
After installing the update your WSUS console (Windows Server Update Services) will report a new version number 6.3.9600.18057