The time of the good old Windows Forms Development for Windowsphones seems over!
One result of this is previous Windows mobile applications will not run on Windows Phone 7 Series.
To be clear, we will continue to work with our partners to deliver new devices based on Windows Mobile 6.5 and will support those products for many years to come, so it’s not as though one line ends as soon as the other begins.
More Detail here:
It will be interesting what OS Enterprise Mobility Devices will be running in the next 3 to 5 Years – CE or WM 6.5? Since CE 6.0 R3 everything seems to be in place for those use cases!