watchOS 5.3 (build 16U6569) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-07-22T19:18:31Z. The update package is 124.35 MB. This is a delta (partial) update that requires 5.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: aedb0aae359d6582b34cca59f7c1f879b58e6ccc.zip.