watchOS 5.3 (build 16U6569) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm), released on 2019-07-22T19:19:32Z. The update package is 106.27 MB. This is a delta (partial) update that requires 5.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 39690ce892a757284d7f1095a35759386b02f351.zip.