watchOS 4.2.2 (build 15S5540a) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2018-01-09T18:12:44Z. The update package is 555.72 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: f8165b77bbc97363a41d55529948df03f94fcd24.zip.