watchOS 5.3 (build 16U5558b) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-06-24T17:25:32Z. The update package is 161.96 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: d4e79cfd6bd2cb0c880d61cbb3b26120aa538778.zip.