watchOS 5.0 (build 16R5303d) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-06-19T17:36:26Z. The update package is 567.74 MB. This is a delta (partial) update that requires 4.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 11c1faf1ece25cd19eaf76ce1d511c4b6428a9fd.zip.