watchOS 6.0 (build 17R5507l) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2019-06-17T17:11:15Z. The update package is 662.7 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: d578ed2eb746c27d3063638ec74757dcd3fb4461.zip.