watchOS 6.1 (build 17S5059e) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2019-10-02T17:10:22Z. The update package is 500.65 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: 840849761af9f32e56abf60c93f9ae2baa2ac5ab.zip.