Microsoft Releases Exchange Server Developer Roadmap

Like many of you, I grew up during the Cold War. One unusual feature of this era was the development of Kremlinologists, people whose job it was to suss out hidden meanings in what the Soviet Union's leadership said, didn't say, did, and didn't do. Every utterance from a Soviet leader was subject to the most careful parsing imaginable. Although the Soviet Union is gone, we still have a sort of Kremlinologist, except now they might better be called Microsoftologists. In fact, we all tend to become Microsoftologists whenever Microsoft announces anything.

This week, Microsoft gave the first public demonstrations of Windows 7; for details, see "Microsoft Talks Windows 7 . . . But Doesn't Say Anything" and "Microsoft Highlights First Unique Windows 7 Feature: Pervasive Multi-Touch." As you might expect, the public unveiling of Vista's successor has generated many more questions than answers, along with a great deal of commentary about what Microsoft did and didn't discuss and what Microsoft senior vice president Steven Sinofsky said—and didn't say—during his interview with Ina Fried.

Last week, Microsoft's Jason Henderson published a blog with some other big company news—information on a topic of great interest to the Exchange Server world: the developer roadmap for future versions of Exchange. You might have missed this announcement because it wasn't on the main Microsoft Exchange Team Blog, but it's worth taking the role of Microsoftologist and examining this news in some detail to see what it tells us about changes coming in the next release of Exchange.

Henderson's post starts by listing some capabilities that will be added to Exchange Web Services. EWS is the future of Exchange development; it's already used in several Microsoft products that talk to Exchange, including Office Communicator 2007 and Microsoft Entourage 2008 SP1, as well as in the Exchange 2007 management tools. I wrote about the benefits of EWS in "Exchange Web Services Offers Development Solution."

However, there are a few things that EWS currently doesn't do. Chief among these limitations: You can't use EWS to access Folder Associated Items, which are data items that are stored in a mailbox but aren't mail items. Server-side mailbox rules and unified messaging (UM) greetings fall into this category, as do some other more esoteric items. When EWS can manipulate these items (in the next version of Exchange, according to Henderson's post), it will be possible to automate actions such as rule creation that currently require a great deal of programming effort.

The bigger news in Henderson's post is the list of APIs that are being cut and de-emphasized in the next major release of Exchange. First on the list is Exchange WWW Distributed Authoring and Versioning (WebDAV), originally introduced in Exchange 2000 Server. The end of WebDAV spells major architectural changes for the Entourage client application as well as to third-party solutions that use DAV for mailbox or calendar access. Store events are also headed for the chopping block, although they aren't widely used in the ISV community. It's not clear how the full range of their capabilities will be replaced by EWS. In fact, the post makes it clear that synchronous events for some types of actions will no longer be supported at all.

Of course, we can infer a lot based on what the post didn't say, too. For example, Henderson gives no information about when the next major release of Exchange will be out or what it will be called. However, the timing of this blog post—just a couple of weeks before the US TechEd shows for IT pros and developers—makes me think that we might see more information about the next Exchange release at the show.

In addition, one question that developers have been asking for a long time—how much longer will MAPI be around?—remains unaddressed, indicating that the answer is probably "a long time."

The handwriting on the wall is pretty clear: If you develop applications for Exchange, you should be using EWS for your future projects. If you're interested in learning how to get started with EWS, Jason Henderson and I are presenting a session on it next week at TechEd 2008 Developers: UNC302, "Building Asynchronous Contextual Collaboration with Microsoft Exchange Web Services," is scheduled for Tuesday, June 3, at 4:45pm. Drop by and say hello!