Apple has released the latest beta version of OS X 10.10.4 to developers and AppleSeed testers.
Details on exactly what comes along with OS X 10.10.4 are still vague, with Apple only saying that the update “improves the stability, compatibility, and security of your Mac”. Developers and AppleSeed testers with the last beta version of OS X installed can download the new build now from the Updates section of the Mac App Store.
Developers can also grab the latest beta build, 14E33b, from the Apple Developer Center.
Source: iMore