watchOS 6.1 (build 17S5083a) is an official Apple over-the-air update for the Apple Watch Series 4 (40mm, LTE), released on 2019-10-23T17:12:32Z. The update package is 370.36 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: 38c108f71d97df7d55d1bbdf2a9c0922fd4bff09.zip.