Microsoft has begun to roll out updates for its Windows Phone 7.5 Mango, the latest set of software upgrades, with over 500 changes, making it the biggest update yet for the mobile platform.

Microsoft plans to release the updates in a phased manner. However, most users are expected to receive the update within four weeks. Current users of the phone will be informed, via an announcement on their phone, when the update is ready for their device.

Microsoft Windows Phone 7.5 Mango has brought in a number of new features that make general operation of the phone an easier task. The communication hub of the Windows Phone has been enhanced with the Mango update supporting LinkedIn and Twitter, in addition to Facebook and integration with Windows Live, which the earlier versions supported.

In addition, Microsoft is introducing an upgraded Groups feature, which will include the ability to send Instant Messages to small groups and threaded conversations for Facebook and Windows Live messaging.

Another feature offered in this update is the long overdue ability to multitask - or switch between apps without being forced to close one or the other.

As of now, the Windows Phone features far fewer apps, when compared to Apple and the Android's marketplace. However, with more developers expressing interest in writing for Mango, this situation is beginning to change.

Compared with RIM BlackBerry, Apple iOS and Google Android in U.S. mobile OS shipments, Microsoft's products are considerably behind. Microsoft is now relying on Mango, as well as its agreements with Nokia - the world's largest producer of mobile handsets - to help make up time and market share. The real test will be the next months, as new handsets preloaded with Mango hit the market.