The later Longhorn gets, the more Microsoft is struggling with how to deliver to customers new features that are ready to go.

On the heels of acknowledging last week that Microsoft might release an interim version of the Windows client before Longhorn, Redmond officials said the company will likely release an interim update on the server side.

"It is likely we will do an update to Windows Server 2003 some time before Longhorn Server ships," said Jeff Price, senior director for Windows server product management. "We are still working through the list of current and future technologies that would be included."

Last week, Microsoft officials acknowledged that the company is considering a number of options—including the possible release of an interim version of Windows between XP and the Windows Longhorn client—to get new "out-of-band" features into the hands of customers. Microsoft also could use additional service packs or other mechanisms to make new technologies available sooner than 2006, the estimated delivery date for the Longhorn client. This collection of feature-delivery options is code-named "XP Reloaded," Microsoft officials said.

Read More on 'Reloaded' Here

On Friday, Microsoft executives said the company is looking at a similar range of feature-delivery options for Windows Server. But Microsoft is strongly leaning toward doing an interim release of Windows Server that would fall between Windows Server 2003, which the company shipped last April, and Windows Longhorn Server. Microsoft has not pinned a delivery target on Windows Server, although some Microsoft executives have suggested it won't be ready until 2007 or later.

Price said there are a variety of code names for the server interim release, one of which is "R2" (for Release 2).

Microsoft already has delivered a number of out-of-band features and functionality for Windows Server 2003, including Active Directory Application Mode (ADAM), iSCSI storage-protocol support and Automated Deployment Services, to name a few. Currently, the Redmond software vendor makes some of these technologies available for free via download from its Web site. Microsoft separately packages and sells other out-of-band technologies—such as the Microsoft Live Communications Server, the real-time communications software that originally was slated to be part of Windows Server 2003.

But now, Microsoft is considering packaging a number of these features into a new Windows Server release, company officials said on Friday, primarily to satisfy customer demand.

The Windows Server platform is continuing to grow, as Microsoft continues to integrate previously separate products and technologies into the base operating system. Microsoft broadened the definition of the "platform" even further last year, by introducing the Windows Server System brand.