Apple Release New Build Mavericks 10.9.3 13D55

Apple today seeded build 13D55 of OS X 10.9.3 to developers, just over a week after releasing the eighth OS X beta, build 13D45a, and nearly two months after the first 10.9.3 beta. 

Apple continues to ask developers to focus on six things:

1. Graphics Drivers
2. Audio
3. Mail
4. Contacts
5. Calendar sync over USB in iTunes
6. Safari

As was discovered with the first beta, 10.9.3 adds new support for 4K displays, offering “Retina” resolutions that improve readability along with support for 60Hz output from the Retina MacBook Pro.