watchOS 4.2.2 (build 15S5536a) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-01-03T18:22:15Z. The update package is 181.15 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: 6b85dc858ea7054aeabf1395d6927cdf20226c5e.zip.