watchOS 4.1 (build 15R5843a) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2017-10-16T17:05:47Z. The update package is 83 MB. This is a delta (partial) update that requires 4.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: b7e3a861e2dd36efc453995182262e3111dfce99.zip.