Last night I noticed a lot of 4.8.* rpms in updates-testing, so I decided to have go:
sudo yum --enablerepo=updates-testing update "KDE Software Compilation"
Now I find that Kwin crashes on login, leaving me without a window manager, and hence unable even to focus on a console window. Kwin is from kde-workspace-4.8.1-2.fc16.x86_64. The problem occurs even when I rename .kde and try again.
Writing this from FVWM (which is very functional and fast BTW :-)
poc