Windows Mobile 6.x Devices Will Not Get Windows Phone 7 Upgrades
At first glance, the HD2 meets Microsoft's criteria for a Windows Phone 7 device. It has a 1GHz Qualcomm processor, high-resolution capacitive touch display, 5-megapixel camera, and a 3.5mm headphone jack. The problem is the phone has two too many buttons. You see, Microsoft has mandated that all Windows Phone 7 devices have just three hardware buttons. The HD2 has five.

Microsoft isn't singling out the HD2 or HTC. Instead, the company is being very strict about the requirements for any Windows Phone 7 device. “Because we have very specific requirements for Windows Phone 7 Series the current phones we have right now will not be upgradable,” Kwan explained.
Because Microsoft hasn't revealed all of the requirements for Windows Phone 7 devices, the HD2 and other high-end phones may be missing other components as well. Tony Wilkinson, Business Operations Director for Microsoft Australia, said, “There are some hardware components that the HD doesn’t have.”
Microsoft is expected to reveal the complete requirements for Windows Phone 7 devices at the MIX developer conference in Las Vegas this month.