iOS 9.1 (build 13B5130b) is an official Apple over-the-air update for the iPhone 6s+, released on 2015-09-30T17:58:14Z. The update package is 1.64 GB. This is a delta (partial) update that requires null already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: d393cc27641669c27abea67e346d5fa43b4d8d4b.zip.