watchOS 4.1 (build 15R5823c) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2017-09-27T16:58:59Z. The update package is 303.76 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: 247f1f98b900b45a93c83733cbd37ba682b705e8.zip.