watchOS 4.3.1 (build 15T6567) is an official Apple over-the-air update for the Apple Watch (38mm), released on 2018-05-29T17:08:25Z. The update package is 57.87 MB. This is a delta (partial) update that requires 4.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 883315328dba22aa3cf193c904b72ca645b01f73.zip.