tvOS 11.4 (build 15L5570a) is an official Apple over-the-air update for the Apple TV 4K, released on 2018-05-07T20:05:38Z. The update package is 64.35 MB. This is a delta (partial) update that requires 11.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 0190c4b0f9c97b0c7b3875bcb92d8dacfdde3574.zip.