Microsoft CEO Steve Ballmer promised “500 new features” for the Windows Phone 7 in a speech at the Microsoft Developer Forum 2011, the Microsoft-dedicated blog WinRumors reported Monday.

The next version of the Windows Phone software, code-named “Mango,” is expected to roll out this fall with greater multitasking abilities and more customizing options for developers.

In his speech, Ballmer said that the features will be revealed at a VIP press event Tuesday and hinted that the company will also be unveiling new Windows phones.

YouTube user WMPowerUser posted part of Ballmer’s speech on the Web. In the excerpt, Ballmer says that Microsoft released the Windows Phone “about a year later than I wish we had” but that the phone is moving forward quickly.

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