Just hours after releasing the first build of OS X 10.9 Mavericks without a "Developer Preview" label to AppleSeed members, Apple has issued the official "Gold Master" version of OS X 10.9 Mavericks to all developers.
A Gold Master build is the same, official version of software that will be released to customers. The fact that Apple has released the GM build to developers almost guarantees users will see the release of OS X 10.9 Mavericks sometime this month. OS X 10.9 Mavericks will introduce more than 200 new features, notably iBooks for Mac, Maps for Mac, tabbed Finder, iCloud Keychain, Tags and more.
In addition to the OS X 10.9 Mavericks GM, Apple also released iPhoto 9.4.7, which "addresses an issue that could cause iPhoto to quit unexpectedly on launch when running OS X Mavericks GM Seed."