I have two domains. DomainA is the parent domain at 2003 functional level. DommainB is the child domain at 2003 functional level.
I have old WinNT machines joined to DomainB so I want to leave this functional level at 2003. I have all 2008R2 domain controllers in DomainA now.
Is it safe to assume I can raise DomainA to 2008R2 functional level and leave DomainB at 2003?