watchOS 5.2.1 (build 16U5079d) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-03-28T17:11:25Z. The update package is 176.51 MB. This is a delta (partial) update that requires 5.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8f5f7fbb32db2e10d19a7e6daa74465f68948dc2.zip.