watchOS 5.3 (build 16U5545c) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-06-11T17:14:08Z. The update package is 455.58 MB. This is a delta (partial) update that requires 5.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 0fcf070c27dc6372c4c43476039f7191d3468c5b.zip.