Microsoft is believed to prepare a major update to its Windows Phone 7 in order to catch up to rivals in web browsing most of all. Codenamed “Mango”, the update is supposed to add HTML5 to the browser and to add support for Silverlight, probably as a plugin. The current update would be larger than the other one or two updates expected to appear early in 2011. it would be somehow equivalent to a Windows Phone 7.5 version, according to ZDNet.

The firmware will also bring support for Southeast Asian language and other unspecified features. It is possible that Microsoft plans to deepen its Exchange support, which is a promise from the past and would be required to improve the standing of Windows Phone 7 next to iOS, Android and BlackBerry, all of them benefiting from substantial Exchange support.

CDMA support as well as copy-and-paste text are features already confirmed for earlier updates. However, deeper changes may appear that may allow more tasks to run in the background.

Both Mango and the rest of the updates may be of crucial importance for Microsoft, which permanently tries to close the gaps between Windows Phone 7 and its rivals in an attempt of completely rebooting its mobile OS strategy. The company had to deal with developer gripes and has also kept the silence upon its early phone sales. Combined with rapid discounting, this suggested that early demand was low enough.