tvOS 13.4 (build 17L256) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2020-03-24T17:17:31Z. The update package is 868.45 MB. This is a delta (partial) update that requires 12.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 48955b431280426615a91fa9c2914ca67afb0b8f.zip.