watchOS 5.0 (build 16R5303d) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-06-19T17:36:27Z. The update package is 563.8 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: 17e8d0110018c02bdf4a90710898a03c751f19e6.zip.