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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.
The beta is available through the Software Update mechanism in the Mac App Store as well as through the Mac Dev Center.
Apple continues to ask developers to focus on Graphics Drivers, Audio, Mail, Contacts and Calendar sync over USB in iTunes, and 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.
