AD Domain forest and domain levels

 

I know this is old information, but I always seem to go back to it, so here it is for me… Oh, you can look at it too.

Forest functional level

 

Forest functional level	Domain controller operating systems supported
Windows 2000 native	Windows Server 2008 R2 Windows Server 2008 Windows Server 2003 Windows 2000
Windows Server 2003	Windows Server “8” Beta Windows Server 2008 R2 Windows Server 2008 Windows Server 2003
Windows Server 2008	Windows Server “8” Beta Windows Server 2008 R2 Windows Server 2008
Windows Server 2008 R2	Windows Server “8” Beta Windows Server 2008 R2
Windows Server “8” Beta	Windows Server “8” Beta

 

Domain functional level

Domain functional level	Domain controller operating systems supported
Windows 2000 native	Windows 2000 Windows Server 2003 Windows Server 2008 Windows Server 2008 R2
Windows Server 2003	Windows Server “8” Beta Windows Server 2008 R2 Windows Server 2008 Windows Server 2003
Windows Server 2008	Windows Server “8” Beta Windows Server 2008 R2 Windows Server 2008
Windows Server 2008 R2	Windows Server “8” Beta Windows Server 2008 R2
Windows Server 8 BETA	Windows Server “8” Beta