iOS 11.4 (build 15F5071a) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-05-07T17:11:38Z. The update package is 248.78 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: 9289709346b1d54401f438ab5b40c95294b69223.zip.