You need a 2012r2 KMS key to activate both hosts and clients at 8.1 level, do you have a valid SA on your 2012 license? Otherwise you will have to use a different host for KMS duties.

In the wake of Microsoft's Windows 10 launch, a one-year grace period was provided for users to activate the system using Windows 7 or 8.1 keys. This functionality, intriguingly, persisted into ...

Windows 8.1 will end support in January, and there are only limited ways to migrate away from Microsoft's ancient OS without paying.

Microsoft has released the public preview of Windows 8.1, and there's plenty to be had in this free update to Windows 8.