Download iPadOS 11.2.1 (15C153) for iPad Pro 12.9-inch (WiFi)

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 iPad6,7
iPadOS Version 11.2.1
Release Date 2017-12-13
Update Date 2017-12-10
Sha1sum
e995052af967f4184ff07ec006c67bdb3324ebd4
Sha256sum
9682ae919a6ea8513920ed4dc635c223cb18914200f72c5a3f32a3b43f23bb8a
md5sum
aa33d07c5a711068bc112273c591967b
Size 2.40 GB
FileName
iPadPro_12.9_11.2.1_15C153_Restore.ipsw
Status

Download IPSW (2.40GB) 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