watchOS 6.1 (build 17S5076a) is an official Apple over-the-air update for the Apple Watch Series 4 (40mm), released on 2019-10-16T17:13:25Z. The update package is 718.53 MB. This is a delta (partial) update that requires 5.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: b94880bce088d78bab7674503778b8e850864f67.zip.