iOS 11.4 (build 15F5079a) is an official Apple over-the-air update for the iPhone 6, released on 2018-05-17T17:02:29Z. The update package is 276.07 MB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: f8c1b96a4977a5233a412431fe39807568289dd7.zip.