watchOS 5.2.1 (build 16U113) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-05-13T17:17:17Z. The update package is 848.52 MB. This is a delta (partial) update that requires 4.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8b197faf1dd3ffa115c4324bea4b5e8d82f2545b.zip.