tvOS 12 brings Dolby Atmos support to Apple TV, zero-sign in support for cable service providers so you don’t have to enter account credentials for each app, new screen savers from the International Space Station, and more.
You’ll need a fourth generation Apple TV or Apple TV 4K to install the update, which will be available for free. The update will auto-install, but if you don’t want to wait for your Apple TV to get around to doing it you can force the update. Here’s how:
Go to the Settings app on your Apple TV, then choose System. Click Software Update, then click the Update option. Be sure to leave your Apple TV plugged in during the update process.