tvOS 13.3.1 (build 17K5792a) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2020-01-14T18:28:55Z. The update package is 96 MB. This is a delta (partial) update that requires 13.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: ecbf86bfd33bd1d82e870f0d70c583d02af11274.zip.