tvOS 12 made its debut at Apple’s Worldwide Developer Conference at the beginning of June. The new tvOS version includes Dolby Atmos audio support, the ability to auto-fill passwords, plus Zero Sign-on for cable TV services. Zero Sign-on lets Apple TV detect which cable service you have and automatically sign in and download apps for available channels.
The tvOS 12 public release is coming this fall, along with iOS 12, watchOS 5, and macOS Mojave.
If you’re interested in trying out the tvOS 12 beta, first enroll in the public beta program at Apple’s website. Then go to Settings > System > Software Updates > Get Beta Updates on your Apple TV.