watchOS 5.3 (build 16U5569a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-07-16T17:14:54Z. The update package is 144.3 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: 5ab98bf980aa80f0e3d6f5850a6b88e763249c2a.zip.