watchOS 4.1 (build 15R5846) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2017-10-20T17:04:13Z. The update package is 155.64 MB. This is a delta (partial) update that requires 4.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 65f0e5e8ac899fab8b14ddd4bcc053cb93711b33.zip.