iOS 11.3 (build 15E5201e) is an official Apple over-the-air update for the iPhone 6s, released on 2018-03-05T18:14:01Z. The update package is 320.16 MB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 779d344648a0023efb235b03d0c2c866b7c495ae.zip.