Download iOS 11.2.6 (15D100) for iPhone 5s (GSM)

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 iPhone6,1
iOS Version 11.2.6
Release Date 2018-02-19
Update Date 2018-02-16
Sha1sum
042248b4b83940fa6af631e21316c07d24b0aa82
Sha256sum
88904a6b534cf4ac35015acfb52a6e880b5437721cb113f82094eef9a698df61
md5sum
d5914ed99c7e780b91a9bbeb004dea1e
Size 2.43 GB
FileName
iPhone_4.0_64bit_11.2.6_15D100_Restore.ipsw
Status

Download IPSW (2.43GB) Check device info
Release Notes

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

iOS 11.2.6 includes bug fixes for your iPhone or iPad. This update:

For information on the security content of Apple software updates, please visit this website: https://support.apple.com/kb/HT201222