tvOS 11.3 (build 15L5186e) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2018-02-21T18:28:52Z. The update package is 137.62 MB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 10933f9decda7aefaf1a0d8091b89524bd0ab703.zip.