Available for some but not all it seems, Apple has just pushed out OS X Mavericks Developer Preview 4. For some reason whilst trying to download in the UK I’m getting an error message saying it’s not available in my country.
Take advantage of new features, like APIs that optimize the new energy saving technologies in OS X Mavericks, as well as new AV Kit frameworks, Sprite Kit, Map Kit, and many powerful additions to existing frameworks.
OS X Mavericks Developer Preview 4 is available as an update from the Mac App Store for systems running OS X Mavericks Developer Preview. To learn more, review the attached release notes.