updated 06:59 am EDT, Sun May 4, 2014
Sure sign that 10.9.3 development is finished, release imminent
In a certain sign that work on the as-yet-unreleased OS X Mavericks 10.9.3 has been completed, Apple has begun seeding employees with an "alpha" build of 10.9.4. The new update could be the last one for Mavericks, as the project codenamed "Syrah" and numbered "OS X 10.10" is expected to be highlighted at June's Worldwide Developer's Conference and debut sometime in the fall. The new seed also signals that public release of 10.9.3 is likely to happen this week.
The 10.9.4 build, amusingly codenamed "Epic," will not be seeded to developers and Appleseed testers until it hits "beta" status, and it is unknown how soon that may happen -- but given the weekly releases of 10.9.3 updates, the first developer version of 10.9.4 could appear in just over two weeks (presuming a release of 10.9.3 on Monday or Tuesday, as has been the company's custom). Apple has recently registered some additional California place names as trademarks for 10.10, and also expanded the beta-testing program to interested users among the public (with a caution that betas are sometimes unstable and prone to bugs, so they should not be used on production machines).
On Friday, Apple seeded an internal build of the 10.9.3 update complete with release notes, normally only done just before public release -- making build 13D57 essentially a "golden master." OS X 10.9.3 restores the feature of local syncing of calendar and contact information directly from iTunes to an iOS device, a feature that was removed in favor of iCloud syncing and brought back based on user feedback from those who wanted sensitive information to be synced locally.
Also being introduced in 10.9.3 is support for pixel doubling for 4K television displays. The feature, a bonus for owners of the latest MacBook Pro models, effectively brings "Retina" screen quality to existing 4K monitor support, as well as expand the number of potential brands of monitor supported. The pixel-doubling will likely expand to other machines in future releases.