Compiz 0.8.4 brings two new plug-ins, many bug fixes, stability improvements, and various KDE4 improvements. Improved between KDE4 and Compiz is window thumbnails are now supported in Plasma window tool-tips, the KDE4 window decorator has been ported to KDE 4.3, and a new Compiz
configuration back-end for KDE4. The new plug-ins found in Compiz 0.8.4 are a KDE4 compatibility plug-in and title bar info.
The Compiz 0.8.4 release announcement with a full change-log can be found on the Compiz mailing list.