watchOS 4.3.1 (build 15T567) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2018-05-29T17:08:27Z. The update package is 823.54 MB. This is a delta (partial) update that requires 2.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 29ca1ce21e90ec8880603001415253d354d26f75.zip.