If you can find the 1.21.0 update via official channels (like a backup from your own device), use that. Otherwise, proceed at your own risk and do not redistribute the files.
: Supports linking with the console version of Mortal Kombat X to unlock exclusive rewards, such as Klassic Kitana. System Requirements DL MORTAL KOMBAT X 1.21.0 Adreno APK for Android