watchOS 4.1 (build 15R5823c) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2017-09-27T16:59:21Z. The update package is 545.32 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: e83f018d9b9a0d40c027cf2891dda51a820b2ca3.zip.