Microsoft has shared with select partners some specifics about what those upgrading to Windows 8 can expect when moving from Windows XP, Windows Vista, and Windows 7.

According to what my contacts have told me, here's the guidance released to them privately by Microsoft this month.

• Users will be able to upgrade to Windows 8 (the name of the entry-level consumer version of the operating system) from Windows 7 Starter, Windows 7 Home Basic, and Windows 7 Home Premium while maintaining their existing Windows settings, personal files, and applications.
• Users will be able to upgrade to Windows 8 Pro from Windows 7 Starter, Windows 7 Home Basic, Windows 7 Home Premium, Windows 7 Professional, and Windows 7 Ultimate while maintaining their existing Windows settings, personal files, and applications.
• Users will be able to upgrade to Windows 8 Enterprise (available to volume licensees with Software Assurance contracts only) from Windows 7 Professional and Windows 7 Enterprise while maintaining their existing Windows settings, personal files, and applications.
• Users will be able to upgrade to Windows 8 from Windows Vista (without SP1 installed) but only personal files (meaning data only) will be maintained. If upgrading from Vista with SP1, personal data and system settings will be maintained.
• Users will be able to upgrade to Windows 8 from Windows XP with Service Pack 3 or higher but only personal files/data will be maintained.

What won't work: Users won't be able to upgrade or keep their Windows settings, files, or applications if doing a cross-language installation. (However, users will be able to keep personal files/data during a cross-language install by using Windows 8 Setup.) Microsoft also is not allowing users interested in doing a cross-architecture -- i.e., 32-bit to 64-bit -- install to do so. Whether running Vista or Windows 7, these users won't be able to keep their existing Windows settings, personal files, and applications or data. They won't be allowed to upgrade this way, period.

Microsoft launched earlier this month its latest Windows Upgrade Offer, by way of which users who purchase Windows 7 PCs between June 2, 2012, and January 31, 2013, can purchase a copy of Windows 8 Pro for $14.99, once it's available.

Windows 8 is expected by many Microsoft watchers to be released to manufacturing next month. General availability on new PCs is expected this fall.