On my desktop system my usual KDE bits (dolphin, kate, etc.) seem fine in the new version. Strangely, of all things, alsaplayer has suddenly stopped working -- it worked yesterday just before the KDE upgrade, and now won't go from krunner or in terminal, and shows no error output. I can't imagine why that would be related to a KDE upgrade, but .... there you have it.
EDIT: On the positive side, Bangarang has stopped crashing, so that's a player alternative now.
EDIT #2: Never mind about alsaplayer -- a zombie alsaplayer process from 2 days ago was preventing it running. Killed the zombie, and problem solved.