watchOS 5.2.1 (build 16U5079d) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2019-03-28T17:11:06Z. The update package is 80.94 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: 23d44336ba9a0e7043dba33a4982e6af7cd9a146.zip.