While technology enthusiasts are still wondering whether the next major Windows Phone version will be based onor the existing Windows Phone codebase, Microsoft this week did provide an answer to one important question: The company revealed that existing Windows Phone apps will indeed run on .
"Any app built today will run on next major Windows Phone version," Microsoft's Brandon Watson wrote on Twitter in response to a rumor from the usual Russian blogger suspects.
Watson, however, also added that Microsoft was "pretty clear about this" fact in its MIX'11 keynote address. I've scoured the keynote transcript but can't find that reference, so it must have been subtle indeed. But it seems unlikely that Microsoft would have even mentioned a Q4 2012 deliverable in a speech from April 2011, given that it was promoting its late 2011 release, codenamed Mango, at that time.
Regardless, Watson's note about current apps running on Windows Phone is indeed news. What it doesn't actually prove, one way or the other, is that Windows Phone 8 is (or is not) based on Windows 8, since such a system could potentially run legacy Windows Phone 7.x in an emulation layer or via virtualization.
Perhaps we'll find out more about Windows Phone 8, codenamed Apollo, this coming month at Mobile World Congress. But I can guarantee that Microsoft will be talking up the next minor Windows Phone update, codenamed Tango, at that show.