Yesterday I delivered the live news about Nokia's plans for Qt 5
with its new features and a road-map to deliver this new tool-kit in the 2012 calendar year. With Qt 5 now being talked about, so is KDE 5.
Aaron Siego wrote a blog post this morning
about Qt 5 and KDE 5. The official KDE short answer is that it's not yet known whether Qt 5 will be greeted by the release of KDE 5. As mentioned yesterday, there shouldn't be many compatibility breaks between Qt 4 and Qt 5 so the KDE 4.x applications should be able to build and run fine or with just minor revisions.
The topic of KDE 5 with Qt 5 is also being hotly debated right now on the KDE development list
The last time KDE 5 was talked about in public when the idea was expressed of merging KDE's libraries withg Qt