"We will offer downgrade rights from Windows 7 to Windows XP in the same way we did with Windows Vista," a Microsoft spokesperson told Channelweb.com. "Volume licensing customers have always had the option of downgrading to a previous version of Windows."

Microsoft has been telling its channel partners that the best way to get their customers ready for Windows 7 is to move to Vista first, but this acknowledgment will virtually guarantee that many companies will simply wait for Windows 7 and skip Vista entirely.

Downgrade rights aren't new, but they're a poignant sign of the market's distaste for Vista. By enabling PC makers to sell PCs with Vista Business or Vista Ultimate PCs, and then perform the XP Professional downgrades as an added service, Microsoft has been able to pump Vista sales numbers while also giving customers a way to avoid Vista's well-publicized struggles.

Microsoft has yet to set a deadline for Windows 7 downgrade rights, since the company hasn't announced timing for Windows 7 availability, the Microsoft spokesperson said. But over the weekend, the AppleInsider blog quoted a purported internal HP communique, which suggests Windows 7 could be available in the October time frame, and that Microsoft will allow OEMs to downgrade Windows 7 Professional PCs to XP until April 30, 2010.

The Microsoft spokesperson declined to comment on the veracity of the HP memo.

Todd Swank, vice president of marketing at system builder Nor-Tech, Burnsville, Minn., said the move to offer Windows 7 downgrade rights reflects the still-strong market demand that exists for XP. "Obviously, Microsoft recognizes that Windows Vista is never going to be accepted as much as they'd like, and realizes that a lot of customers are going to remain on XP until Windows 7 comes out," Swank said.

Despite the de facto XP extension that Windows 7 downgrades represent, Microsoft on April 14 will stop offering free bug fixes for customers running retail versions of XP. After that date, XP users will have to pay for support on a per-incident basis for bug fixes, although Microsoft will still deliver XP security updates for free until 2014.

Microsoft has also been accused of illegally profiting from XP downgrade rights. In February, a Los Angeles resident filed a class action lawsuit in Seattle federal court, accusing Microsoft of forcing customers to buy Vista PCs so that it could charge them for XP downgrades, claims that Microsoft has denied.