watchOS 4.2.2 (build 15S5534a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2017-12-19T18:06:11Z. The update package is 150.79 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: 197f02ee97aa7ee2c66a4511f16ac52fec869a1d.zip.