iOS 11.4 (build 15F79) is an official Apple over-the-air update for the iPhone 6s+, released on 2018-05-29T17:16:41Z. The update package is 743.94 MB. This is a delta (partial) update that requires 11.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 9e1ff865164312cd9ab149fda2838947deca6806.zip.