Download iPadOS 11.2.1 (15C153) for iPad 5 (Cellular)

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 iPad6,12
iPadOS Version 11.2.1
Release Date 2017-12-13
Update Date 2017-12-10
Sha1sum
67eedd78b86cc76a381d75bfe14c493284a70f5d
Sha256sum
bf7eb64c2b2eb0b4e615e5ff2ccafd7e79bab263049728007fa0bda288feee0c
md5sum
c55f447137f903a578338d0ecd189157
Size 2.35 GB
FileName
iPad_64bit_TouchID_ASTC_11.2.1_15C153_Restore.ipsw
Status

Download IPSW (2.35GB) Check device info
Release Notes

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

iOS 11.2.1 fixes bugs including an issue that could disable remote access to shared users of the Home app.

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

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