The Windows Server 2012 R2 forest functional level provides all the features that are available in the Windows Server 2012 ...

The Windows Server 2012 R2 forest functional level provides all the features that are available in the Windows Server 2012 forest functional level and additional features.
Any new domains that are created in this forest will operate by default at the Windows Server 2012 R2 domain functional level. For more information, see http://go.microsoft.com/fwlink/?LinkId=296707.