watchOS 4.1 (build 15R846) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2017-10-20T17:05:48Z. The update package is 552.45 MB. This is a delta (partial) update that requires 3.2.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c77a815bfda92499f4cc866a69d0c5bb5627755b.zip.