watchOS 5.3 (build 16U569) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-07-22T19:19:58Z. The update package is 147.5 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: a1398c49698c9bbf084680c4e6766bd815916d96.zip.