tvOS 12.3 (build 16M5151a) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2019-05-07T17:18:22Z. The update package is 36.64 MB. This is a delta (partial) update that requires 12.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e55314a3405b73bc6cd7ef501186fda36797c99a.zip.