Running in a test environment, I have some major issues with Windows 8.1 with ZCM 11 SP3 and the Windows 8.1 update.

I had to change update.xml to get this update to import into ZCC, all I did was change GUID as described in this thread:

When I install the ZCM agent, the install is a success, and the machine will reboot.
After reboot the new update starts installing, but when this process is done, the machine will never get back into windows.

The Win8 repair screen appears saying theres an irrecoverable error.
c:\windows\system32\logfiles\srt\srttrail.txt claims that registry is damaged.

I do not have access to the Internet from this machine, all I have installed is ZCM 11SP3.