Just a couple of weeks after the release of OS X Mavericks Developer Preview 3, Apple has released a new version of their next generation OS, OS X Mavericks Developer Preview 4.
The latest developer version of Apple OS Mavericks is available as a software update from the app store for developers who previously installed the developer preview 3 and also from Apple’s website.
You can find out full details about OS X Mavericks Developer Preview 4 over at the Apple Developer website.
Source MacRumors