iOS 9.9.11.0.2 (build 15A421) is an official Apple over-the-air update for the iPhone 6, released on 2017-10-03T17:04:23Z. The update package is 1.26 GB. This is a delta (partial) update that requires 9.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 813c34ec219c77e11248b0e7dc7a3e215883f6fa.zip.