It seems that existing Windows Mobile applications will unfortunately be incompatible with Windows Mobile 7 phones.
Microsoft Partner Group Program Manager for the Windows Phone Application Platform & Developer Experience, Charlie Kindel, had the following to say:
“To enable the fantastic user experiences you’ve seen in the Windows Phone 7 Series demos so far we’ve had to break from the past.To deliver what developers expect in the developer platform we’ve had to change how phone apps were written. One result of this is previous Windows mobile applications will not run on Windows Phone 7 Series.”
