iOS 9.3.1 (build 13E238) is an official Apple over-the-air update for the iPhone 6+, released on 2016-03-31T16:55:16Z. The update package is 1.24 GB. This is a delta (partial) update that requires 8.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c0ce40797a16baa6f953db16978f13e58ea459a2.zip.