Users currently running Windows XP Service Pack 3 (SP3) or earlier, and Windows Vista RTM, SP1 or the upcoming SP2, will be able to upgrade to Windows 7, Microsoft informed as it introduced the SKU lineup for the next version of the Windows client. There will be essentially three upgrade models for Windows users according to the Redmond company, depending on the source operating system, namely XP to Windows 7, Vista to Windows 7 and of course Windows 7 to Windows 7.

As far as Windows XP users are concerned, Microsoft indicated that upgrade licenses of Windows 7 will be available to them, superseding the existing XP licenses, and that the upgrade media can be used in order to move to Windows 7. However, the transition implies a clean installation of Windows 7 rather than an actual in-place upgrade. Still, the deal has to please XP users, as they will get the full Windows 7 bits at a discounted upgrade price. Users are advised to back up all their data from the partition where XP is installed before deploying Windows 7, just to be on the safe side.

For Vista, users will indeed be able to enjoy in-place upgrades to Windows 7. In this context, Windows 7 deployments on top of Windows Vista will leave everything in place, from installed applications to data. The upgrade process however is extremely slow compared to a clean installation of Windows 7. The software giant revealed that Vista editions (Home Basic, Home Premium, Business and Ultimate) can be upgraded to the corresponding or higher editions of Windows 7 (Home Premium, Professional or Ultimate).

At the same time, just as was the case with Vista, users will be able to jump from one edition of Windows 7 to another, provided that the upgrade is done to a superseding SKU, thanks to the Anytime Upgrade feature. Just a reminder, the full line-up of Windows 7 editions is: Starter, Home Basic, Home Premium, Professional, Enterprise and Ultimate.

“For Windows 7, we are using a single image for all SKUs. This means the bits for all the editions are already on your computer if you are running Windows 7. With Windows Anytime Upgrade, users can unlock and upgrade to a different SKU much easier than before,” revealed Brandon LeBlanc, Windows Communications manager on the Windows Client Communications Team. “In Windows 7, each SKU is a superset of the previous SKU. No features are lost on upgrade.”

Windows 7 Beta is available for download here.

Product keys to activate Windows 7 Beta are available here.