watchOS 5.3 (build 16U569) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2019-07-22T19:16:15Z. The update package is 883.55 MB. This is a delta (partial) update that requires 4.2.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: d22f5a3f3477e499c9ac132c74c719b50e51cc82.zip.