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 760.54 MB. This is a delta (partial) update that requires 10.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: eb5794030403c5348eed26c069081698a70d8ad2.zip.