watchOS 4.2.2 (build 15S5530d) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2017-12-13T21:09:28Z. The update package is 181.03 MB. This is a delta (partial) update that requires 4.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 95f368e89feb33ea00b9768d6eb5dc0010ddeade.zip.