iOS 9.2.1 (build 13D15) is an official Apple over-the-air update for the iPhone 6+, released on 2016-01-20T21:16:14Z. The update package is 1.2 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: 25e0ed0cb86b2302a29e92ed5a19da8ed264be54.zip.