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 252.17 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: c9320fdb5be9ed74a1e058c3c966feadf2ec76e1.zip.