watchOS 5.0 (build 16R5313d) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2018-07-03T17:11:27Z. The update package is 625.09 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: d65890288f9b0de80357998107609cfce16ec23d.zip.