I can’t even open the app now that I upgraded to iOs 13 – List Master Pro - Your Lists Review

I have used List Master since about 2014. I have a lot of important information stored in the lists. Since I upgraded to the latest iOs yesterday it won’t open and I don’t need to upgrade it in the App Store either. Lists I emailed to myself are also not opening. This is more than a major headache - it is a disaster. I guess I can’t rely on one app for a lot of my important information and have to go to paper backup. What’s the point then?
Review by iac1003 on List Master Pro - Your Lists.