iOS 9.9.11.0.2 (build 15A421) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2017-10-03T17:03:27Z. The update package is 1.47 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: be0258f629b5d8690a68e19c993d085079adec6d.zip.