watchOS 4.2.2 (build 15S5536a) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2018-01-03T18:22:34Z. The update package is 50.43 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: 9d478e2419d0bbc4e258fa4891cb643a4731f21c.zip.