watchOS 4.3 (build 15T5176c) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2018-02-07T18:09:25Z. The update package is 313.71 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: 5d5974e58dc1c25b21c580df748eb37c5e42dd6b.zip.