watchOS 5.3.7 (build 16U674) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2020-05-18T17:31:43Z. The update package is 45.99 MB. This is a delta (partial) update that requires 5.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 47c0f568eda327595e9f6ba90be239239760b7f8.zip.