watchOS 5.2.1 (build 16U5113a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2019-05-07T17:18:59Z. The update package is 159.69 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: 14c1ee19ce40dd74e86fa2b8cdc98f54070a30da.zip.