Microsoft has revealed it will ship certain editions of Windows 7 with up to 18 months downgrade rights.
According to Redmond Channel Partner, the vendor will offer users of Windows 7 Professional and Ultimate the option to switch to Windows Vista or Windows XP until April 1st, 2011.
Volume licensees will also be able to downgrade to any previous version of the OS, as has always been the case with new releases.
However, Microsoft has warned that downgrade rights for XP may end sooner than 18 months if it releases a service pack. Vista will be unaffected.