iOS 11.4 (build 15F5037c) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-04-02T17:06:53Z. The update package is 252.76 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: 684d60a8dd45e8d5f59cbc58ab55c7d611f885c8.zip.