I have a Windows Server 2003 SP2 machine with IIS and ADAM SP1. Our software vendor is now requiring windows server 2003 R2 for it's next version and I'm wondering if I will have any issues running the R2 upgrade. I see a lot of Microsoft articles referencing upgrading from 2003 or 2003 SP1 but nothing talking about upgrading to R2 from SP2.
I don't think there is any difference in the version of ADAM included with R2 and the downloadable version. You will have to reapply SP2 after you upgrade. As with any upgrade the best way to tell if you are going to have problems is to try it on a test server first.
R2 is really just the additional optional components as well as some upgraded capability to some of the existing ones