As reported back in March by us, at today's Windows Phone Developer Summit, Microsoft confirmed, that non of today's Windows Phones, including latest devices like the highly popular Nokia Lumia 900, will receive an upgrade to Windows Phone 8, which was announced earlier today. Instead, Microsoft will offer a Windows Phone 7.8 upgrade which mimics the new Windows Phone 8 Start Screen but will still run on the soon outdated Window CE kernel, today's Windows Phones run on. Since Windows Phone 8 and Windows 8 will have a shared API-set, this means advanced Windows Phone 8 features like app and games ,that use that native programming, aren't supported on first generation Windows Phone.
All today's Windows Phone users will get is the Start Screen which comes with some new and improved elements like variable tile sizes, which allows to select between small, medium and so-called "double wide" tiles and new tile color.
Cheers ~ Arne