watchOS 5.3 (build 16U5569a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-07-16T17:14:53Z. The update package is 170.93 MB. This is a delta (partial) update that requires 5.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 539685390f399da7c5ee6f2539404a33849c9039.zip.