watchOS 4.2.2 (build 15S5534a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2017-12-19T18:05:58Z. The update package is 64.85 MB. This is a delta (partial) update that requires 4.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 37695ab2a4795977cbc49ac022b2af8059499bf6.zip.