Microsoft has released the first service pack for Exchange Server 2007, fixing software bugs and adding some new features to make the product more stable and useful for business customers.

However, Microsoft's Exchange partners said there are still improvements that could be made so the latest version of Exchange can provide customers with a more complete end-to-end messaging architecture.

Users can download Exchange Server 2007 Service Pack 1 (SP1) from Microsoft's website. Anticipating the long-awaited release of Windows Server 2008 early next year, Microsoft added support for that product into SP1, as well as features that allow for integration between Exchange Server 2007 and Office Communications Server 2007.

Windows Server 2008 support in particular is important for customers, because there is clustering technology in Windows Server 2008 that replaces existing technology in Windows Server 2000 and 2003 that has become obsolete, said Keith McCall, chief technology officer and founder of Azaleos in Seattle. Azaleos offers an Exchange hardware appliance and other email management and archiving services.

Windows Server 2008 support in SP1 provides Exchange customers with "a more effective high-availability solution for managing infrastructure," he said.

For the companies offering Exchange Server as a hosted service, SP1 has technology to resolve problems the product had with multi-tenancy, said Rurik Bradbury, vice president of strategy for Microsoft hosting partner Intermedia. Multitenancy is when a single Exchange Server environment serves multiple customers. Improvements to multitenancy in SP1 make the product more stable for hosting partners, said Bradbury, whose company has been testing the service pack.

Microsoft also did an about-face and reinstalled the "public folders" feature of Outlook Web Access, the Web-based version of the Outlook e-mail client, in SP1, he said. Workgroups within an organisation traditionally could share information through public folders on Outlook Web Access. However, Microsoft "was trying to make everyone move" to its Office SharePoint Server to provide this feature, "but now backtracked in the face of an outcry from Exchange customers," Bradbury said.

In addition to these improvements, Microsoft also added a new disaster-recovery feature to Exchange called Standby Continuous Replication (SCR), the company said. SCR allows administrators to put a server running Exchange in a separate geographic location to provide failover. But Bradbury was critical of the new feature, saying that providing this kind of failover is "difficult and would still involve email downtime," as well as increase the cost of Exchange Server because it requires deploying an extra server for the product.

One feature that Azaleos' McCall said is still missing from Exchange is message archiving for storage management and compliance purposes. He said Microsoft partners have been requesting this addition to the product for a while, but Microsoft has made other features such as business continuity and high availability its primary goals for Exchange until now. Azaleos offers its own archiving service for Exchange, McCall said.

Before releasing Exchange Server 2007 SP1, Microsoft enlisted 270,000 beta testers to kick the software's tires as part of its Technology Adoption Program (TAP), with more than 30,000 of those testing the product with Windows Server 2008. The company is providing TAP customer experiences online for users to read.

Microsoft released Exchange Server 2007 about a year ago, and said that more than 3,000 companies representing more than 1 million seats are using it. Still, McCall said that he has seen hesitation among customers to move from Exchange Server 2003 to 2007, but that SP1 should encourage more to make the leap.