watchOS 5.0.1 (build 16R381) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-09-27T20:08:36Z. The update package is 724.01 MB. This is a delta (partial) update that requires 4.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 51d38052f8639371588cd56ac9c2d285e4e361c1.zip.