watchOS 5.3 (build 16U6569) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-07-22T19:19:59Z. The update package is 141.88 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: 7a2c684c1c99fef916acc41362caa03cb39368d5.zip.