Who I have the same questioned this topic

My "new" phone is not working, so I recenlty dug out my Motorola Razr to use for the time being. I downloaded Message + since all my devices are synced towards it. I am familiar with the program and know it needs to be the "default messaging app." Since I can't find where to turn that on, I seem to be getting notifications from my defualt text app as well as Message +. How/where do I fix this? I remember it use to automatically prompt to make the switch, but that prompt doesn't seem to be popping up.

Thank you.