watchOS 5.0.1 (build 16R381) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-09-27T20:08:24Z. The update package is 961.38 MB. This is a delta (partial) update that requires 3.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e95279436436e5a925d7b1b7d5f9fb66d5bf4d27.zip.