I can't understand.

I can not understand.
I opened my CAPTURE ONE EXPRESS 22 and it asked me to do an update. I clicked on download and now I find myself in addition to my program also CAPTURE ONE 21. But how is it possible? I checked the installation date and CAPTURE ONE 21 is installed today. But if I already had 22 why did he make me install 21? And why do I now have two programs ?! Which one should I use !?