watchOS 5.1.1 (build 16R6600) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-11-05T18:05:40Z. The update package is 393.92 MB. This is a delta (partial) update that requires 5.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 2ef7b25f93597ca7a7073a34ef3fbcd1a7973253.zip.