Download iOS 11.4 (15F79) for iPhone 6+

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 iPhone7,1
iOS Version 11.4
Release Date 2018-05-29
Update Date 2018-05-18
Sha1sum
2bb3f264370c24446289eb033094323957037cca
Sha256sum
6f87e69c6281a2a48b18a661a0ca11d4e0c688e091df5ef3dad36d4c12222988
md5sum
dd54b6585226b3bdf63638de16e045fc
Size 2.72 GB
FileName
iPhone_5.5_11.4_15F79_Restore.ipsw
Status

Download IPSW (2.72GB) Check device info
Release Notes

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

iOS 11.4 includes AirPlay 2 multi-room audio, support for HomePod stereo pairs, and Messages in iCloud. This update also includes bug fixes and improvements.

AirPlay 2

HomePod stereo pair

Messages in iCloud

Other improvements and fixes

For information on the security content of Apple software updates, please visit this website:

https://support.apple.com/kb/HT201222