watchOS 5.3 (build 16U6569) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-07-22T19:18:28Z. The update package is 156.47 MB. This is a delta (partial) update that requires 5.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: d5a1ae7602bb2a4067dc9e506b87f3c7925e8121.zip.