URT bundle can be used to check if the upgrade will be successful or not. We can fix the error and then can schedule a window to ugrade the ISE.
Step 2> Download the URT bundle from ISE.
Step 3> Upload the URT bundle on repository.
Step 4> Run the URT bundle on secondary node or on standalone node.
application install <URT file name > <repository name>
If for some reason the URT fails it will create a file share that file with TAC for further troubleshooting.