Apple has released Mac OS X 10.3.9.
The update is available through Software Update and as a direct download directly from Apple's website. Apple has released a similar update for Mac OS X 10.3 Server.
The company says the new software: "Delivers overall improved compatibility and reliability for Mac OS X v10.3 Panther and is recommended for all users".
Along with some bug and security fixes, the software update improves: file sharing and directory services reliability for mixed Mac and PC networks; Mail, Safari and Stickies application reliability; and better compatibility for third party applications and devices. More information on Apple's website.
The Server update offers better reliability of OPen Directory authentication requests and Active Directory integration. It also provides better AFP performance when listing large files; a better version of Cyrus for more reliable email message storage and better Ethernet reliability on Xserve.