iOS 9.3 (build 13E5181d) is an official Apple over-the-air update for the iPhone 6s+, released on 2016-01-11T22:09:32Z. The update package is 1.66 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1e4a78b170817159489c1baf8cbcb218ccb2b527.zip.