While waiting for Mac OS X 10.4 to be released... Apple is still working on tweaks and fixes for Mac OS X 10.3. On Friday, Apple seeded Mac OS X 10.3.9 to developers.
The indicated areas of testing include Bluetooth, DVD Player, FireWire devices, Modems (internal and external), Networking, Printing, Safari, Terminal, USB devices, general system usability and reliability.
Bug fixes listed include USB 2.0 Hard Drive Mouting, CUPS drivers, Directory Services performance, Video Driver fixes, Fax and modem driver fixes, and more.