UPDATED TO v6.3.0!
You might receive an error that the app is not being installed from Playstore, in that case you have to do the following:
1. Install the MOD first.
2. Download and install LuckyPatcher from LuckyPatchers.com.
3. Click on "Injustice 2"
4. Click on "Menu of Patches"
5. Click on "Remove License Verification"
6. Click on "Auto modes"
7. Choose first option "Auto Mode(dex)
8. Click "Apply"
9. Wait the patch to finish, launch the game and enjoy!