iOS 11.4 (build 15F79) is an official Apple over-the-air update for the iPhone 6s+, released on 2018-05-29T17:16:43Z. The update package is 688.53 MB. This is a delta (partial) update that requires 11.2.5 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a93b14cd77dbedcf0638c9105ca7d7a1d4a4b364.zip.