Important for those automatically updating through the app: do not install this update if you are on 10.4! Instead, download the 10.4 version here and install it manually. Note that future upgrades will handle per-OS updates properly, as 3.1 includes code changes to support this.
Snow Leopard support and 64-bit binary
Better connection handling and stability on 10.5 and above
Cleanup of menu items and actions to reflect current Facebook site design
Resolves crashes on startup
Note that alerts for "New photo comments" are no longer available as Facebook has stopped providing this functionality