watchOS 4.3 (build 15T5176c) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-02-07T18:09:41Z. The update package is 306.57 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: dd8b13ff0f7fe84b63a9097c8a0e6d211bd5604b.zip.