watchOS 5.2.1 (build 16U113) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2019-05-13T17:17:05Z. The update package is 881.81 MB. This is a delta (partial) update that requires 4.2.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: fa7de06000f0b6bb107a75d0695ff752bcbe72df.zip.