watchOS 4.1 (build 15R5843a) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2017-10-16T17:05:26Z. The update package is 548.06 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: 6019ef383bd04c2057690720536191412f1c9ea1.zip.