Both Jupgrade products are poorly documented and lock up frequently. The debug mode gives no useful information. One is left to search their forum for clues to getting it to run correctly. There you'll find lots of other frustrated users.
As I dug through clues to getting it to run, each attempt required a time consuming fresh re-install of Joomla.
After 10 or so attempts I finally got Jupgrade Pro to run but the special extension I purchased for CB apparently didn't.
I next purchased a support ticket option, which was responded to a day later by a tech who didn't know how to access cpanel.
While waiting for support answers I went ahead an complete a manual migration of my site in a much more efficient manner than all the time I wasted trying to get Jupgrade & Jupgrade Pro to work.
It appears from the review here that the product works well for some. For me however...it was a time consuming, frustrating disaster.