Download iOS 11.1.1 (15B150) for iPhone 6s

You will have to note that you can only restore signed IPSW firmware files using iTunes or 3utools.

❌ This IPSW firmware is not being Signed by Apple

Firmware Identifier iPhone8,1
iOS Version 11.1.1
Release Date 2017-11-09
Update Date 2017-11-07
Sha1sum
d1f7af40736670432f32059f4e409ac84b42462d
Sha256sum
d58801c53e3787aaab26a6c277591be4dbb1a7e7b98784efa088254913dbddca
md5sum
b31b1bd3ec3197e9ad0bc9f3b19d7594
Size 2.53 GB
FileName
iPhone_4.7_11.1.1_15B150_Restore.ipsw
Status

Download IPSW (2.53GB) Check device info
Release Notes

It should be noted that these are the official release notes for the from Apple

iOS 11.1.1 includes bug fixes for your iPhone or iPad. This update: