Despite numerous issues with their online developer portal, which has been offline since Thursday due to a security breach, Apple has nevertheless seeded the fourth Developer Preview of OS X Mavericks to developers. The update was seeded right on schedule, exactly two weeks following Developer Preview 3.
As with the previous developer previews, the fourth developer build continues to address various bugs and add performance enhancements ahead of the public release of OS X Mavericks. The update weighs in at 1.72GB is available through the Mac App Store on machines that already have a previous Mavericks preview installed. The update weighs in at 1.27GB.
OS X Mavericks is staled for public release later this fall, and boasts over 200 new features.