[Gazdok]

Can any old windows 7 / mobile phone be upgraded to windows 8?
Will I get backward compatibility for programms / apps that were running on W7?
Would a SD slot that was not functional on W7 become functional with W8?

[Flagz]

Can any old windows 7 / mobile phone be upgraded to windows 8?
Will I get backward compatibility for programms / apps that were running on W7?
Would a SD slot that was not functional on W7 become functional with W8?

NO, old WP7 would not be updated to windows 8, but instead Windows 7.8 which bring many improvements that's WP8 also had. You won't have everything. As for old W 6.5 phones, I think the phone of the century HTC HD2 has a hack available to upgrade to WP7 and WP8. By default though, its not upgradable to any.

[XENOPHOS]

No no and no.

The WP7 devices are working on an older kernel. The new WP8 devices are on the NT Kernel newer one that is.
There is no way u can run it on older devices. I would recommend don't even try.

Sent from my RaZr on MIUI.