Apple issued the first Mac OS X 10.5.3 seed (9d10) to developers yesterday. The latest update to Apple's Mac OS X Leopard addresses dozens of outstanding issues.
Fixes range from Dashboard, Parental Controls, iCal Synchronization, memory leaks and stability issues. All in all, 75 distinct bug fixes are listed in the accompanying seed notes.
A few known issues remain, and Apple typically seeds a number of developer builds for testing before releasing the final update to customers. While these point releases generally provide bug and stability fixes only, the 10.5.2 seed also addressed some user interface complaints. The current version of Mac OS X (10.5.2) was released in February 2008.