Updating an Existing 2008 R2 KMS Server to Support Windows 8.1 and 2012 R2

In order to make a existing KMS running 2008 R2 compatibility for Windows 2012 R2 and Windows 8.1 licensing, we need to run and update to the VAMT services on the server.

Windows 7 and Office 2010 use VAMT 2.0, Where as Windows 8.1, 2012 R2 and Office 2013 use VAMT 3.0

So you need to first download VAMT 3.0 which is included in the Windows 8.1-2012 R2 ADK  that can be downloaded here:

http://www.microsoft.com/en-us/download/details.aspx?id=39982

It's a 5GB download so it will take a while depending on your connection speed.

Once you've got it downloaded you'll only need to install the VAMT portion:

After you've got that installed, you'll need to add your Windows 8.1/2012 R2 KMS Key via command prompt as seen below, to add and activate the new Windows License: