watchOS 4.1 (build 15R5823c) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2017-09-27T16:59:30Z. The update package is 275.43 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: a1c98f85a4e648c96fd4e5b359e1625540e2fd5e.zip.