Microsoft plans to roll out Windows Phone 7.8 — the previously announced update for Windows Phone 7.5 users — in early 2013, Windows Phone head Terry Myerson said in an official blog post.
Owners of Windows Phone 7 and 7.5 devices are unable to upgrade to Windows Phone 8 because the hardware for WP7.x devices won’t work with some of the more advanced offerings of WP8.
Microsoft is instead offering those owners WP7.8, which will include some of the features of WP8, including resizable Live Tiles on the Start screen and more theme and accent colors. Angry Birds Space and Angry Birds Star Wars will also be coming to WP7.5 and 7.8, according to the blog post.
WP7.8 will also come already installed on some new devices, launching at lower price points in many countries.