iOS 9.3 (build 13E233) is an official Apple over-the-air update for the iPhone 6, released on 2016-03-21T18:56:30Z. The update package is 1.07 GB. This is a delta (partial) update that requires 8.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e6e29229f47f36f9a2d7525f94c16c2d52657395.zip.