iOS 11.4 (build 15F5037c) is an official Apple over-the-air update for the iPhone X (GSM), released on 2018-04-02T17:06:51Z. The update package is 287.68 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: 7344bbb8c9b98817f0cfaefb6ce12ae83c368384.zip.