iOS 11.1.1 (build 15B150) is an official Apple over-the-air update for the iPhone 6s+, released on 2017-11-09T18:11:10Z. The update package is 1.2 GB. This is a delta (partial) update that requires 10.3.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1b34ba3ed4358e7d8c198d3476a783e8b8dfff4b.zip.