Installed version 5.6 of Lightroom but when I initiate the program it comes up version 5.4 what is going on

I just instelled version 5.6 of LR but when I initiate the program it says it is version 5.4 and I get repeated notifications to upgrade to the latest which is 5.6. Do I need to uninstall ver 5.4 and the install 5.6. Don`t want to lose my catalog in the process. How do I keep current?