watchOS 5.2.1 (build 16U113) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-05-13T17:17:19Z. The update package is 844.35 MB. This is a delta (partial) update that requires 4.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a1e321bcabfca2ff1c509113152a593773db13a0.zip.