watchOS 4.3.1 (build 15T5555c) is an official Apple over-the-air update for the Apple Watch Series 2 (38mm), released on 2018-05-01T17:06:40Z. The update package is 63.16 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: a47c8c9f5e19ee781019eb5bd48dc60a1b7edd79.zip.