Apple released tvOS 11.4.1 for Apple TV on Monday. The maintenance release includes no known new features, and it keeps Apple TV up with iOS 11.4.1, which was also released Monday.
The update is also expected to include a variety of security patches, but Apple has not yet added tvOS 11.4.1 to the Apple Security Updates webpage.
To download the update go to Settings > System > Software Update, where it’s a click or two away.