watchOS 5.0 (build 16R5303d) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2018-06-19T17:36:46Z. The update package is 590.12 MB. This is a delta (partial) update that requires 4.2.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: aff55d911f7763a153b2c7f19b4f7f1ffef97f16.zip.