Microsoft will allow users of Windows 8 Pro to downgrade their new PCs to Windows 7 or even Vista, according to the operating system's licensing agreement.

Not surprisingly, users may not downgrade to the still-used-but-slated-for-retirement Windows XP.

Downgrade rights -- which let customers replace a newer version of Windows with an older edition without paying for two copies -- are available only in Windows 8 Pro. That fits with previous practice: Only Windows 7 Professional, for instance, was allocated downgrade rights.

"Instead of using the Windows 8 Pro software, you may use one of the following earlier versions: Windows 7 Professional or Windows Vista Business," states the software license agreement for the version of Windows 8 Pro that will be installed by computer makers (OEMs) on new PCs.

Windows XP Professional, which was one of the allowed downgrades for Windows 7 Professional, was not named. Windows XP will fall off Microsoft's support list in April 2014.

One licensing expert noticed XP was AWOL.

"So no downgrade rights to XP. Also note that the soon-to-come Office 2013 will not support XP. So we can see they are trying to strangle the life out of XP," said Kenny Chan, a technology specialist for CDW, in message earlier this month on a LinkedIn thread dedicated to Microsoft licensing professionals.

"What I don't know is how long Microsoft will keep XP available for download on VLSC for volume licensing customers after the debut of Windows 8," Chan added. VLSC (Volume License Service Center) is the online portal for companies that have signed volume licensing agreements with Microsoft.

Unlike consumers or small businesses, corporations armed with enterprise licensing agreements, including the annuity-like Software Assurance, are allowed to downgrade from any version of Windows to any previous edition.

Downgrade rights became noteworthy after Windows Vista's 2007 launch when many users, frustrated at that edition's problems, mutinied and dropped back to XP.

Computerworld