Windows Mobile 6.x users won't get Windows Phone 7 upgrade
Even though the HD2 has a fast enough processor, a nice touch display, and a good enough camera, Microsoft says it can't be upgraded to Windows Phone 7 because it has too many buttons. Apparently, a Windows Phone 7 Series device has to have three buttons, but the HTC HD2 has five.
Or, to put it terms that Monty Python fans will understand, Microsoft is saying that the number of the buttons shall be three. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three.
Five is right out.
It's not just HTC's device, though. None of the other phones Microsoft currently supports are eligible for the upgrade, either. This just seems like a case of Microsoft taking a page from the Apple handbook and controlling the hardware experience for its hot new software. MS has a lot riding on Windows Phone 7 Series, and it makes sense that they wouldn't want to take the blame for any compatibility issues with the previous generation of hardware.
Windows Mobile 6.x users WILL be getting an upgrade, though: to Windows Mobile 6.5.3, just before WinMo gets rebranded as "Windows Mobile Classic." It will come with magnifier technology, so you can use the touchscreens on older devices without a stylus.