Apple has seeded the second public beta of tvOS 18 to users for testing. This follows the release of a fourth developer beta yesterday.
tvOS 18 is a major operating system update for the Apple TV with new features like InSight, updates to Enhance Dialogue and subtitles, new Apple Fitness+, Apple Music, and FaceTime capabilities, and more.
To try out the public beta, sign up for the Apple Beta Software Program here, then open the Settings app on your Apple TV and go to System > Software Update. After a few seconds, a 'Get Beta Updates' row will appear. Select the row and choose 'tvOS 18 Public Beta' from the options that appear.