watchOS 5.3 (build 16U5569a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-07-16T17:14:52Z. The update package is 454.85 MB. This is a delta (partial) update that requires 5.1.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7ba729d24719edd699fbc6a09af24afcc4aa90ed.zip.