As many others these days, I’m messing around with Windows 8.1 and was looking into upgrading our KMS to support the new OS.
Here’s what I did:
1) Download and install following update on your KMS host: http://support.microsoft.com/kb/2885698 and reboot the server.
2) Uninstall current KMS key from an elevated command prompt using: slmgr.vbs /upk
3) Install the new Server 2012 R2 KMS key also from an elevated prompt using: slmgr.vbs /ipk NEWKEYGOESHERE
4) Activate the new key running slmgr.vbs /ato
…and voila: our KMS is ready for Windows 8.1 and Server 2012 R2 🙂