Supported upgrades for domain controllers to Windows 2008 (Melting Pot in CorpNet)

Currently we are running Win2k3 SP1, R2, SP2, Win2k8 Beta3, RC0, RC1, and RTM Escrow idomain controllers in production...  Since we're running some downlevel servers in the environment and I was interested in what is supported to be upgraded to Windows 2008 when we sign off and the the DVDs start getting pressed.  Luckily a mail came by on one of our discussion aliases that has the details I (we) desire.

  • You can have DCs with down-level OS down to Windows 2000 SP4 in the same forest along with WS2008 DCs.
  • This means you can have forests with a mix of WS2008, WS2003 SP2, WS2003 R2, WS2003 SP1 and Win2K SP4 (please have in mind that this depends on the forest and domain functional levels).
  • If you have a down-level only forest (i.e. no WS2008) and want to introduce a new WS2008 you will need to run ADPrep (ForestPrep and DomainPrep).
  • You can run ADPrep having down-level OS down to Win2K SP4, you don’t need to have all of them with WS03 SP2.
  • However if you are going to in-place upgrade any of the down-level DCs, these have to be at least WS2003 SP1.

Refs:

Upgrading Active Directory Domains to Windows Server 2008 AD DS Domains

What Service Packs can be upgraded to Windows 2008