Yesterday, Microsoft made the first public announcement about Exchange Server 2010 SP1, and it's a whopper! Over the years, Microsoft has vacillated between two opposite poles: putting only bug fixes into service packs versus adding new features along with the bug fixes. I'd put SP1 squarely in the latter category because it adds a ton of extremely valuable new features to what is already the most significant release of Exchange in some time.

The first major SP1 change I want to talk about involves the way that the Personal Archive feature works. In Exchange 2010 RTM, Personal Archive mailboxes must be in the same mailbox database as the primary mailbox they support. This requirement prevents you from using the Personal Archive functionality with less-expensive, slower storage, and it puts limits on how you provision mailbox databases for users. This situation alone has slowed down Exchange 2010 deployments because the utility of Personal Archives is limited by not being able to move them to alternate storage.

SP1 removes this limitation so that a Personal Archive mailbox can be created in any mailbox database in the organization. It's essentially treated as any other mailbox would be except that it's linked to its primary mailbox. In keeping with the idea that it's much like a regular mailbox, SP1 also lets you grant delegate access to users' Personal Archives.

Another difficulty with the RTM version of the Personal Archive feature is its client compatibility: It requires Outlook 2010 or Outlook Web App (OWA) 2010. It's hard to imagine that many organizations would deploy Personal Archives given that you can't actually buy the desktop version of Outlook that supports them yet, and in fact that seems to be what's happened. SP1 adds Personal Archive support for Outlook 2007, which should help unblock a number of deployments. Microsoft is keeping mum about exactly how this support will be implemented, but you should expect it to include an Outlook add-on of some sort—so be thinking now about how you'd deploy such a plug-in across all your clients if Personal Archives are important to you.

SP1 includes a bunch of very welcome improvements to the Exchange Management Console (EMC) and the Exchange Control Panel (ECP). The biggest items here are support for Role Based Access Control (RBAC) and full support for retention tags and policies. RBAC is a great Exchange 2010 feature, but in its current incarnation it's needlessly difficult to use, so having it integrated into ECP will undoubtedly speed its adoption.

OWA and Exchange ActiveSync get some tasty new features as well, notably a series of interface tweaks that make OWA look more like a web app and less like a desktop app. I'm delighted that OWA in SP1 will finally support themes again because they provide a very useful, and supported, way to brand and customize the appearance of OWA for companies that want to do so.

The Exchange Team Blog has an expanded list of SP1 features available in the post "Yes Virginia, there is an Exchange Server 2010 SP1," and the post also includes a short video featuring the delightful duo of Ian Hameroff and Ann Vu. Expect to see a few more surprises in SP1 when it's finally released; Microsoft almost always leaves a few things out of their initial public announcements. I look forward to seeing what those surprises are!