Yes, you knew it was coming! …
Alongside seeding the second beta of iOS 7 to developers of the ADC earlier tonight, Apple has also just flicked the switch to send the second ‘Developer Preview’ of its upcoming desktop operating system live for developers.
OS X Mavericks (Build 13A476u) – which can be downloaded from Apple’s Developer Portal using a special Mac App Store promo code – requires a 64-bit, Intel-based Mac running either OS X 10.6.7 Snow Leopard (or later). Apple notes that you must have at least 8GB of free disk space to install OS X 10.9.
This is a pre-release version of OS X Mavericks. OS X Mavericks Developer Preview 2 is available as an update from the Mac App Store for Macs running OS X Mavericks Developer Preview.
It is so far unclear what has changed in this build.
UPDATE: Install Notes
Apple is stressing the fact that OS X Mavericks Developer Preview 2 is pre-release software. The company says that you shouldn’t use this pre-release software in a “commercial operating environment” or with important data.
“You should back up all of your data before installing this software and regularly back up data while using the software. You will not be able to upgrade from the OS X Mavericks Developer Preview to the final release,” the release notes read.
If an installation of OS X Mavericks Developer Preview 2 fails, Apple says that you should “try using Disk Utility from a Recovery HD” to repair the disk.
In addition to seeding the second ‘Developer Preview’ of OS X Mavericks, Apple is tonight also making available Xcode 5 Developer Preview 2, which it notes is required to develop applications for OS X 10.9.