watchOS 5.2.1 (build 16U5101c) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-04-22T17:13:14Z. The update package is 135.97 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: e3da687b469b7a0227c203d7ce89ef0b1ccaaa53.zip.