watchOS 4.2.2 (build 15S5534a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2017-12-19T18:05:53Z. The update package is 214.87 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: 6a83b5a9a1ab3bc74fad456cb8c8cd52f0a27818.zip.