iOS 9.9.11.3.1 (build 15E302) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-04-24T17:09:47Z. The update package is 1.59 GB. This is a delta (partial) update that requires 8.4.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 66cf73d89f700edc5c9a4b8b9489fc2ca6bd00d6.zip.