watchOS 6.0 (build 17R5491t) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2019-06-03T19:28:24Z. The update package is 653.8 MB. This is a delta (partial) update that requires 5.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4da038c3d60827544960bbc9cf936bbe2d873375.zip.