iOS 11.4 (build 15F5049c) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-04-16T17:08:14Z. The update package is 218.07 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: b730e0495b2c4fa4ee89790eab40f432ccc4a92b.zip.