watchOS 6.1 (build 17S5054e) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-09-23T17:04:54Z. The update package is 711.56 MB. This is a delta (partial) update that requires 5.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 0d4f90b37acf20752368caacf34b6a028df62cbc.zip.