The single most sad bit about the summit today has been the news of existing Windows Phone devices not being eligible for Windows Phone 8. yes that’s true all phones that are on sale or expected to come in the next few months will not be upgradeable to Windows Phone 8, the shiny new version of Microsoft’s mobile platform.

There are many reasons for the update not coming to existing devices, apart from existing hardware and the fact that some of the features require NFC and others bits to be present. This is not the case with existing device as many of them don’t have NFC and dual core or more processors.

However as a middle path, Microsoft will be providing some of the features of Windows Phone 8 to existing users, for now this is relegated to just the new start screen. The update will be available vita OTA and upon applying the update users will get a look of Windows Phone 8, but it won’t be WP8. There’s no word on what else will be available apart from re-sizable tiles.

Microsoft’s Greg Sullivan revealed why the company chose not to offer a direct upgrade from Windows Phone 7.x to Windows Phone 8.

When you pull that Lumia out of your pocket after you’ve received that 7.8 update, it will look and feel the same as a Windows Phone 8 device,

claims Sullivan.

Because you don’t have a multicore chip and don’t have some of these other elements, it didn’t make sense for us to make those investments for devices that couldn’t really exploit them.

Joe Belfiore also said something similar on the Windows Phone blog -

Windows Phone 8 is a generation shift in technology, which means that it will not run on existing hardware. BUT we care deeply about our existing customers and want to keep their phones fresh, so we’re providing the new Start screen in this new update.

So there you have it, officially there’s no update that will come to the Lumia and Omnia devices and even for HTC’s devices too. However I’ve heard that if you still want to install WP8 on your phone it might be available from MS, but they will assume no responsibility for the upgrade and won’t offer any support too.