iOS 10.2.1 (build 14D27) is an official Apple over-the-air update for the iPhone 6s, released on 2017-01-23T18:08:35Z. The update package is 368.71 MB. This is a delta (partial) update that requires 10.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 922b40eb39f20d6021c26ad1d3c607eb892df3b1.zip.