“In order to get the next update of its Windows operating system out the door, Microsoft will delay some of the key improvements that had been planned, sources close to the company said Friday.

The company should announce a road map for Longhorn, its revision to Windows XP, later on Friday. The changes will allow the company to meet its most recent timetable: to have a beta version ready by next year and a final release for 2006.

Longhorn was originally supposed to have three major changes: a new file system, WinFS; a new graphics and presentation engine known as Avalon; and Indigo, a Web services and communication architecture.

Microsoft is making changes to all three pillars. WinFS will be available as a beta when the Longhorn release comes out as a client. Avalon and Indigo will be part of Longhorn, but also made available separately at the time the client ships for Windows XP and Windows Server 2003, sources said.

According to the sources, Microsoft decided to make some trade-offs to deliver the features that corporate customers, manufacturers and consumers wanted on time.”