Microsoft

An Overview of the Active Directory Domains And Trusts Console

You can raise the forest functional level to Windows Server 2008 if all domain controllers in the forest have been raised to the Windows Server 2008 level. To raise the forest functional level, click the Active Directory Domains And Trusts branch and choose Action | Raise Forest Functional Level. If all domains in the forest have been raised to the Windows Server 2008 level, the console displays the Raise Forest Functional Level dialog box.