watchOS 4.1 (build 15R5823c) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2017-09-27T16:58:58Z. The update package is 542.18 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: 3f3b1ee9c0cd15a2a61f1137c73eaf3440415667.zip.