iOS 9.2.1 (build 13D15) is an official Apple over-the-air update for the iPhone 6, released on 2016-01-19T18:20:40Z. The update package is 1.12 GB. This is a delta (partial) update that requires 8.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 42dabac028eabed276dc85c5908c46a60ed8db29.zip.