Microsoft explained that Windows Phone 8 has been designed around next-generation phones. Basic hardware requirements include multi-core processors, new graphics engines, higher screen resolutions, microSD storage and near field communication (NFC) radios. A phone that was capable of running Windows 7 can’t handle all of that – so upgrading to it is out of the question.
Fortunately, there is some good news. To show they are not too mean-spirited, Microsoft has prepared an update to Windows phone 7, namely Windows Phone 7.8. While it won’t give you all of the functionality of WP8, it will give you the look and feel by way of the “live tiles” design.
Given this information, it would probably be good to hold off on any Windows Phone purchases until WP8 goes live.