iOS 9.3.1 (build 13E238) is an official Apple over-the-air update for the iPhone 5 (GSM), released on 2016-03-31T16:54:40Z. The update package is 19.98 MB. 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: d320584c27e4efa8d58dbedfe0c1d3cde0aaf95f.zip.