watchOS 5.3 (build 16U569) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-07-22T19:20:25Z. The update package is 494.69 MB. This is a delta (partial) update that requires 5.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 87b07fb450d8037fcdc29afc23afa66bb94df828.zip.