iOS 11.4 (build 15F5077a) is an official Apple over-the-air update for the iPhone X (GSM), released on 2018-05-14T17:17:13Z. The update package is 299.98 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: 04d1e9fec948a3455f34cbb9fd0579e1ba3c9557.zip.