watchOS 5.2.1 (build 16U5110a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-04-29T17:39:40Z. The update package is 138.69 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: 49fa5f1f559b30368b4888b085495ead7b8da943.zip.