iOS 11.4.1 (build 15G77) is an official Apple over-the-air update for the iPhone 6s, released on 2018-07-09T17:10:11Z. The update package is 736.71 MB. This is a delta (partial) update that requires 11.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 36242af70c393763bfd76ec4bee5e0dcf202292c.zip.