iOS 11.0.3 (build 15A432) is an official Apple over-the-air update for the iPhone 6s, released on 2017-10-11T17:07:53Z. The update package is 1.08 GB. This is a delta (partial) update that requires 10.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 390f2dca78ad151b34e5b147e0b45e5b25fef1c4.zip.