Extend the activation time for evaluation version of Windows

For Microsoft 20-410~412 Windows Server 2012 R2 class, we download the evaluation version of Windows to try
things out and do our class projects. But some of you may find that the evaluation license only valid for 90 days.
So to solve this problem the simplest way is to use slmgr.vbs

Open Administrator CMD or Powershell and type:

slmgr /rearm 

It should works on Windows 8, 10, 2012, 2012 R2 and 2016.
After you done it the system should extend the activation time so you can keep doing your project :).

If you want to get more detail about the Windows machines’ activation, license and expiration date info your could try:

slmgr /dlv
slmgr /xpr