watchOS 4.2.2 (build 15S5536a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2018-01-03T18:22:30Z. The update package is 50.41 MB. This is a delta (partial) update that requires 4.2.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 30afd530de8f6c149c9dfebec814d34d837ae08a.zip.