tvOS 12.4 (build 16M5526d) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2019-05-15T17:19:58Z. The update package is 74.72 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: 167511e602a7ed53c96cfd95e7b00318d0701926.zip.