The latest OS X 10.9.4 Mavericks build 13E19 marks the return to Apple’s usual one-week build release interval, coming eight days after the second beta was issued earlier in June. The initial seed was issued at the end of May following the public release of OS X 10.9.3
As with the previous OS X 10.9.3 betas, Apple is asking developers to focus on Graphics Drivers and Safari. The new OS X 10.9.4 releases tack on extra areas of interest including Bluetooth, Audio Drivers, Finder and the App Store.