Detailed changes can always be found in the Detailed Change Log, but here are some of the major features of this version.
jEdit 4.4 now requires Java 1.6.
Buffersets have been re-engineered, and simplified. All editpanes have the same bufferset scope, so changes to the scope affects all editpanes immediately.
Introduction of a new ThreadUtilities class implementing a threadpool using Java 1.6 Concurrent API. Use this instead of VFSManager's WorkThreadPool, which is now deprecated. Related: A new Task Monitor dockable which will eventually replace the I/O progress monitor, for showing progress of tasks. Still TODO: rewrite VFSManager + all plugins to use ThreadUtilities instead of WorkThreadPool.
New DataTransfer API to allow for rich text copy/paste.