watchOS 6.1 (build 17S5076a) is an official Apple over-the-air update for the Apple Watch Series 4 (40mm, LTE), released on 2019-10-16T17:13:50Z. The update package is 457.65 MB. This is a delta (partial) update that requires 6.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8da3f66a8490dc36ef6ffb70293a45dfc874789d.zip.