watchOS 6.1 (build 17S5054e) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-09-23T17:04:55Z. The update package is 711.89 MB. This is a delta (partial) update that requires 5.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a87af1b2a9c78d90f93fa983b3b22e1bb9a927ed.zip.