Applies To: Windows Server 2008 R2, Windows Server 2012
Specifies the name of the selected domain.
Current domain functional level
Specifies the current setting of the domain functional level.
After you set this option to a certain value, you cannot roll back or lower the domain functional level, with one exception: when you raise the domain functional level to Windows Server 2008 R2 and if the forest functional level is Windows Server 2008 or lower, you have the option of rolling the domain functional level back to Windows Server 2008.
You can lower the domain functional level only from Windows Server 2008 R2 to Windows Server 2008. If the domain functional level is set to Windows Server 2008 R2, it cannot be rolled back, for example, to Windows Server 2003.
The functional level of a domain or forest defines only the set of Windows Server operating systems that can run on domain controllers, along with the set of available features. It does not define the client operating systems that are supported in the domain or forest.