watchOS 5.3 (build 16U5545c) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-06-11T17:14:10Z. The update package is 154.71 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: 5a958c8d0851635a480d1e156413dc1b91a2b069.zip.