Windows Phone 7.5 devices won't be upgraded to Windows Phone 8

Nokia Lumia 900

Microsoft announced its next-generation Windows Phone 8 mobile platform today and unveiled a number of new features that users have been clamoring for. Unfortunately for existing Windows Phone 7.5 users, an upgrade will not be available to Windows Phone 8 when it comes to the market. Microsoft says that there were too many underlying platform changes to make the update possible. However, all is not lost, as the software giant plans to release a Windows Phone 7.8 update for legacy devices that includes the new Start screen feature coming in Windows Phone 8. The company did not say exactly when the Windows Phone 7.8 update would be made available.