This post is a little late, I know. We've been taking care of a few Microsoft partner requirements.
And speaking of Microsoft–Exchange 2010 Service Pack 1 is out!
If you haven't already seen it, Microsoft's Exchange Team announced the service pack on their blog. According to them and many beta users, OWA is the big beneficiary this round.
I also want to point out the release notes here. There are some things you should know before upgrading to SP1…things that affect OCS. (Naturally, given the nature of this blog!)
If you plan to upgrade, let me make the following recommendations.
A. Do a Full Upgrade of the Unified Messaging Server. You have the option for a Partial Upgrade, which runs an Exchange 2007 UM Server alongside the 2010 UM Server.
Problem is, OCS 2007 R2 can't determine what version your users' mailboxes are, 2007 or 2010! So if it sends a call to an Exchange 2007 UM Server, but the user's mailbox is on a 2010 UM Server? The call will fail.
Avoid this by doing a Full Upgrade.
B. Run all hotfixes available for your .NET Framework before the upgrade begins. This avoids a potential error which could cause trouble with mailbox moves.
C. Planning to use OCS 2010/Communications Server “14” when it's released? You can (and should) install Exchange 2010 SP1 first. Its new UM Server contains tools that work with both OCS 2007 R2 and OCS 2010. For example, you can migrate SIP dial plans between servers.
Scott Lowe's “Servers and Storage” blog on TechRepublic has a nice screenshot-heavy capabilities overview on Exchange 2010 SP1. There's a lot of little improvements all throughout Exchange with SP1; a few extra references in your initial research will only help.
Already done your SP1 upgrade? Let us know how it's treating you. If you're planning one, what issues are you concerned about?