watchOS 5.3.8 (build 16U680) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2020-07-15T17:28:13Z. The update package is 40.22 MB. This is a delta (partial) update that requires 5.3.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 241634972e1b8a574a828343220bf4b740de6533.zip.