Windows Phone version history

This page provides details for the version history of the Microsoft's Windows Phone branded mobile operating systems, from the release of Windows Phone 7 in October 2010, which was preceded by Windows Mobile version 6.x. == Windows Phone 7 == Windows Phone 7 was the first release of the Windows Phone mobile client operating system, released worldwide on October 21, 2010, and in the United States on November 8, 2010.

Source: Wikipedia — Windows Phone version history (CC BY-SA 4.0)