watchOS 4.2.2 (build 15S5540a) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-01-09T18:13:09Z. The update package is 57.95 MB. This is a delta (partial) update that requires 4.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: f3f08af8910a412ff57af65df81e3fe43f4621b9.zip.