With the Windows Phone Summit wrapping up in California, we’re starting to see the various bits of information about what’s next for current generation Windows Phone devices blend into a cohesive story. So here’s what we’ve, been able to piece together so far.

Microsoft seems to have been hammering this fact home, and so we will too. No Windows Phone 7.0 or 7.5 devices will be upgradable to the next big release from Microsoft. Instead these devices will be treated to a smaller update that will allow them to use a newly updated Start Screen. Currently Microsoft isn’t discussing what other features might be included in Windows Phone 7.8.

There are also particulars in the way Windows Phone 7.8 devices will interact with the Windows Phone Marketplace once it’s Windows Phone 8 counterparts hit the streets. Apps that are written specifically for Windows Phone 8 will not be compatible with Windows Phone 7.5 devices. Developers will be able to continue deploy apps for Windows Phone 7.8 devices, though so the impact of splitting the application ecosystem should be minimal in the short term.

Those are really all of the details we have for older devices at this point. We’re sure a lot of you aren’t into too thrilled about the line being drawn in the sand, (particularly Nokia Lumia 900 and 910 users).