Microsoft not sure if it's going to upgrade WP7 to Windows Phone 8
We've expressed concern about the prospects of upgrading current first—and second—generation Windows Phone handsets to Windows Phone 8, codenamed Apollo, when it is released later this year. Microsoft refuses to commit publicly, and we've heard from employees within the company that some or all current users won't be able to upgrade, even those who buy new, second-generation devices. Others have heard similar tales.
Nuno Silva, who works as developer evangelist at Microsoft, seemingly delivered a clear answer to the upgrade question in an interview with Portuguese technology site Zwame, but Microsoft won't corroborate the statement. Though the original hour-long interview video appears to have been pulled, a fragment of it was saved by WMPoweruser.
