iOS 11.1.1 (build 15B150) is an official Apple over-the-air update for the iPhone 6s+, released on 2017-11-09T18:11:11Z. The update package is 241.83 MB. This is a delta (partial) update that requires 11.0.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 33932f5a8ca3a31c941c4b7ad718365e1c07a6a5.zip.