iOS 9.3.1 (build 13E238) is an official Apple over-the-air update for the iPhone 6+, released on 2016-03-31T16:55:17Z. The update package is 436.65 MB. This is a delta (partial) update that requires 9.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: cc4bfe197e9c33eb999bf9d91e9636139d29cc2a.zip.