watchOS 4.1 (build 15R5823c) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2017-09-27T16:59:00Z. The update package is 208.58 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: 259e6a534f2b67b5ba914e039dd5ae4d2e9cc0ca.zip.