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 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.

At the 2011 Mobile World Congress, Steve Ballmer announced a major update to Windows Phone 7 due toward the end of the year, Windows Phone 7.5, codenamed Mango. The new OS would address many of the platform's shortcomings, including a mobile version of Internet Explorer 9 that supports the same web standards and graphical capability as the desktop version, multi-tasking of third-party apps, Twitter integration for the People Hub, and Windows Live SkyDrive access. Although the OS internally identifies itself as version 7.1, it is marketed as version 7.5 in all published materials intended for end-users.

Microsoft started rolling out Windows Phone 7.5 to both the United States and International markets on September 27, 2011. The first phones that came pre-loaded with Windows Phone 7.5 were released in the last quarter of 2011.

A minor update released in 2012 known as Tango, along with other bug fixes, would also lower the hardware requirements to allow for devices with 800 MHz CPUs and 256 MB of RAM to run Windows Phone. Certain resource-intensive features are also disabled on these phones, and the Windows Phone Store will also prevent the installation of apps that are considered to be too intensive for use on weaker hardware. The lower requirements were adopted in order to allow the development of lower-cost devices, particularly to target emerging markets such as China.

Windows Phone 7.8 is the final major release of Windows Phone 7. It consists exclusively of user interface improvements backported from Windows Phone 8, as existing Windows Phone 7 devices cannot be upgraded due to changes to its architecture and hardware requirements. These include a home screen with the ability to resize live tiles, new accent color options, and an updated lock screen with support for Bing wallpapers. Unlike Windows Phone 8, the lock screen does not allow third-party apps to display notifications on it.

General Distribution Release 1, a minor update known as Portico was rolled out in December 2012 that brought some improvements and bugfixes, including enhancements in Messaging, more efficient Bluetooth connectivity, and an "always-on" setting for WiFi connections, among other additional platform updates

Microsoft rolled out a package of minor updates called General Distribution Release 2, beginning in July 2013 and spanning the following months, depending on the manufacturer and carrier. Along with this update Nokia released its own update which updated the firmware of the user, namely Lumia Amber, which was available for only Lumia phones. The update brought many camera improvements and fixed some bugs in the cameras of existing Lumia phones.