Microsoft yesterday revealed the first major update to its Windows Phone 7 mobile operating system, which is reportedly already powering many of the upcoming handsets from Nokia.

The mobile OS update, dubbed Mango, includes a number of enhancements from the previous version, including the introduction of conversation threads for chats, text messages and social media channels; improve Live Tiles for better multitasking and HTML5 support for Internet Explorer 9.

Microsoft's internet search engine Bing is also getting some improvements as well, the company said, including enhanced search capabilities for the web, music and video.

"With Mango, Windows Phone takes a major step forward in redefining how people communicate and use apps and the Internet, giving you better results with less effort," said Andy Lees, president of Microsoft's mobile communications business.

In February, Microsoft and Nokia announced a new alliance in which new Nokia handsets will be based on Microsoft's mobile OS. Though no devices have leaked yet, a Nokia representative recently told Engadget that more than one Nokia device is running the new Mango version of WP7.