watchOS 5.3 (build 16U569) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2019-07-22T17:26:47Z. The update package is 831.98 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: a259e62e4618fa8bb8a6be0979996e652c8c32a6.zip.