tvOS 13.3.1 (build 17K5775c) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2019-12-17T18:16:02Z. The update package is 98.65 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: 09b6a1c51c57618c001d48bae1c515ec0ada4c10.zip.