watchOS 5.1.1 (build 16R6600) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-11-05T18:05:54Z. The update package is 392.73 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: e8fcd736cac1d63e3f35e117a3a8e7432c6f5dd8.zip.