Update: Jill Lovato from the Windows PR team sent us a note to clarify a few things. Namely, that the downgrade right is specific to the EULA for Windows 7, not the tech support deadline for Windows 7 in January 2020. Customers will not be able to buy a PC with downgrade rights to XP after Windows 7 is retired from market – which according to policy is 2 years after the next version of Windows ships.

Last year, after being met with disapproval from analysts and consumers alike, Microsoft prolonged the availability of its Windows XP downgrade option to 18 months instead of six as originally planned. The decision meant that companies would have until April of 2011 to move off of XP. But now the aging operating system is getting yet another lease of life, as Microsoft decided to extend that period until 2020 throughout the Windows 7 lifecycle.

Microsoft's Brandon LeBlanc said in a recent blog post that Windows 7 has gained a lot of traction among consumers, and with Windows powering approximately 96% of the enterprise desktop market it's a no-brainer for most firms to eventually transition as well. However, 74% of businesses still use Windows XP, and for a lot of them the cost of upgrading their entire infrastructure to support Windows 7 is not financially justifiable just yet.

So, while few consumers may want to downgrade from Windows 7 to XP, it's another story in the corporate world where businesses often want to standardize on a single operating system to simplify machine management. The downgrade rights will be available only from OEM copies of Windows 7 Professional or Ultimate – those that are pre-installed by computer makers. Curiously, the announcement coincides with the end of support for XP SP2, so anyone who still wants to be covered by Microsoft support will at least have to move to Windows XP's Service Pack 3.