On July 29, 2013, Apple released, together with iOS 7 beta 4, the new Apple TV Software beta 3. In the release notes it is named 5.4 Beta Seed 3, but after updating my Apple TV 3 I found in the section ‘About’ documented that it is in real Apple TV Software 6.0 (6646.16.1). It seems, that together with iOS 7, the Apple TV will get to a major update to version 6.0 (The predecessor beta was named 5.4 on the Apple TV).
The current software version can be found in the ‘About’ section of the Apple TV:
The most significant new feature is ‘Touch to Configure’ meaning you are able to automatically set up, restore or reset your Apple TV via near Bluetooth with your iPhone or iPad. iPad 2 and iPhone 4 are not supported.