watchOS 5.0 (build 16R5303d) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-06-19T17:36:28Z. The update package is 563.46 MB. This is a delta (partial) update that requires 4.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c668d0641297982109ef796b63b3f9b28f52a30e.zip.