Microsoft has gone public with a tentative date for its third service pack for Windows XP. And that date —
the latter half of 2007 — is considerably later than many company watchers were expecting.

Microsoft has published the due-date for Windows XP Service Pack 3 (SP3) on its Windows Lifecycle Web site. While Microsoft characterized the date as "preliminary," it is still as much as a year later than a number of customers, partners and industry analysts had been anticipating.

Last April, according to at least one Web report, Microsoft CEO Steve Ballmer said Microsoft was consideringreleasing SP3 before Longhorn (now Windows Vista) shipped. Windows Vista is expected to ship in the second or third quarter of 2006.

Microsoft also has published "latter half of 2006" as the tentative release date for the second service pack for Windows Server 2003. The "preliminary" due date for Windows Server 2003 Service Pack 2 (SP2) date jibes with what industry experts were expecting.

Microsoft has not made public an official list of planned fixes (and new features, if any) that will be part of either the Windows Server 2003 SP2 or Windows XP SP3 releases.

Last year, TheHotFix.Net site publishes a regularly updated list of likely XP SP3 features and fixes. But Microsoft officials have not said whether that list is accurate.

Microsoft released the most recent collection of bug fixes and patches for Windows XP in the form of XP Service Pack (SP2) in August of 2004. While Microsoft did not go so far as to christen XP SP2 a new version of Windows, the release included so many new features that a number of company watchers considered it to be a full-fledged operating-system upgrade in its own right.

Microsoft officials attributed some of the delays in Longhorn/Windows Vista to SP2. Officials claimed the company's decision to reassign developers working on Vista to finishing and testing SP2 had a negative impact on Vista's schedule.

It is unclear if Microsoft is pushing back SP3's delivery date in order to avoid a similar negative impact on Vista's schedule. It's also unclear whether Microsoft may be holding back SP3 in order to help stimulate upgrade demand for Vista.

Microsoft officials were not available for comment by the time this article was published.

Last week, Microsoft amended dates that it published to its Lifecycle Web site for the phasing out of support for Windows XP Home Edition. Microsoft was scheduled to end mainstream support for all of its consumer editions of XP by December 30, 2006. Last week, the company changed the consumer XP support-cutoff dates to December 30, 2008.

"Service packs should be on a predictable and reliable schedule," said Michael Cherry, an analyst with Directions on Microsoft. "I have said that SP1 should be six months after launch, regardless of how big it is or how many bugs it fixes. SP2 should be on the first anniversary. The last SP should come on the transition from mainstream to extended support. There could also be an SP (3) at the mid point between SP2 and the last one."

"SPs should be slightly front-end loaded, that is, there should be more of them early in the lifecycle," Cherry added. "SP2 should likely be the biggest. But you have to keep in mind that Microsoft is under no obligation to release even a single SP under the terms of mainstream or extended support. It is solely at their discretion to release anything but separate bug fixes when they feel like it."

(This story was updated on Tuesday to include analyst Cherry's quotes.)

This is an edited version of an article which originally appeared in the January 11, 2005, version of the Microsoft Watch newsletter. If you'd like to see what other Microsoft scoops you might be missing, why not sign up here for a no-risk, 14-day free trial subscription to the Microsoft Watch newsletter?