tvOS 11.3 (build 15L211) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2018-03-29T17:05:13Z. The update package is 762.17 MB. This is a delta (partial) update that requires 10.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5094ffdaeab88b8e5709aafcbd79b8225ca02f04.zip.