There was a big upgrade to KDE 4.11.2 and, not long after, I noticed my beloved window changes sound effects were gone. Especially the desktop change notifications, maximize, minimize, and close windows sounds that I always configure. In systemsettings notifications, I saw the title and sound fields were blank in kwin window manager system notification configuration. Guess that's not coming back.
https://bugs.kde.org/show_bug.cgi?id=324941