updated 10:03 pm EDT, Wed May 7, 2014
Follows internal release to AppleCare workers earlier in the day
In an unusual move, Apple has released a tenth version of the forthcoming OS X 10.9.3 beta to developers, in a slightly different build than one distributed internally to AppleCare representatives earlier on Wednesday. Testers are also being offered a new beta of the Safari web browser, version 7.0.4.
Apple originally began including final release notes with an earlier internally-distributed build, 13D57. After sending 13D62 to AppleCare employees, Apple is seeding 13D61 to developers and public beta testers who recently signed up under a new program. Everything in the latest builds appears to be identical to the earlier release, including areas testers should focus on and the release notes.
The Safari 7.0.4 beta, the first with that version number, is likely being seeded to test the program against changes made in 10.9.3, which is still expected to be released this week. The OS update is expected to include the return of local iTunes syncing of contacts and calendars with iOS devices, as well as new support for scaling Retina MacBook Pros for 4K monitors that would bring the "Retina" quality to mirrored or extended mode to supported 4K monitors through pixel doubling.
Testing has already commenced on the next version of OS X Mavericks, version 10.9.4, as well. The updates are available from Apple's Developer portal, or through Software Update for registered developers and beta testers.