watchOS 4.2.3 (build 15S6600b) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2018-02-19T21:17:18Z. The update package is 39.14 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: f4de00157cf79aa0c3a22b6ef18748454defb1d1.zip.