watchOS 5.2.1 (build 16U5110a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-04-29T17:39:14Z. The update package is 143.86 MB. This is a delta (partial) update that requires 5.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: f78f59d3c6ac87bc905b6f61d3fbeb4cc90f8337.zip.