The move is one step past Microsoft's drop of XP support for Internet Explorer 9, which was just released last month.
When the final build of the browser hits, you must have Windows 7 SP1 installed, says the company.
Reveals Microsoft:
Windows Vista customers have a great browsing experience with IE9, but in building IE10 we are focused on continuing to drive the kind of innovation that only happens when you take advantage of the ongoing improvements in modern operating systems and modern hardware.
Regarding Windows Vista, our decision with IE9 was not to build to the lowest common denominator. With IE9 we made the decision to help unlock the best Web experience possible, which means taking advantage of everything around the browser -- including Windows 7 and modern PC hardware.