[ActiveDir] Windows 2003 Server R2 Schema extentions Question

[Myrick, Todd \(NIH/CC/DNA\) [E]]

Title: RE: [ActiveDir] User Accounts

What are the features of Windows 2003 Server R2 that require the new AD schema extensions in order to be used in a mixed 2000, 2003, 2003 R2 environment.  Specifically I am concerned about the clustering, and new enterprise printing functions and wonder if it is okay to deploy them without the extensions.   Thanks,   Todd Myrick