iOS 11.4 (build 15F79) is an official Apple over-the-air update for the iPhone 6, released on 2018-05-29T17:16:19Z. The update package is 733.12 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: 11a735dccd110f033d0e3b4c22cbd1f9e2dd94fa.zip.