watchOS 5.3 (build 16U569) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-07-22T19:18:03Z. The update package is 485.26 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: 2f91e5514ad80a34d164e391d12bc63f54bd502c.zip.