iOS 11.4 (build 15F5079a) is an official Apple over-the-air update for the iPhone SE, released on 2018-05-17T17:02:32Z. The update package is 249.62 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: dbdd34f39c3a3bf7cdbddaea79fee9975cc60824.zip.