iOS 9.2.1 (build 13D15) is an official Apple over-the-air update for the iPhone 6s, released on 2016-01-19T18:20:44Z. The update package is 309.67 MB. This is a delta (partial) update that requires 9.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c0e8c050bc34e1e44b3f3796d68d760176432a7c.zip.