iOS 11.4 (build 15F5061d) is an official Apple over-the-air update for the iPhone 6s, released on 2018-05-01T17:06:06Z. The update package is 182.53 MB. This is a delta (partial) update that requires 11.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 0ce20303d7caeb659a71df7c90ae879a7f62dd4a.zip.