Crashes with split screen on Ipad

Hi. I am testing out MiraCheck (v5.1) on my new iPad gen 9 and like it, however I encounter a show-stopping problem f not resolved. Split screen worked fine yesterday, but today both apps shuts down and the home screen reappears. I can toggle the apps in full screen view, but not split the screen to see both. Split screen still works with other apps. It is worth noting that I updated to iOS 15.5 over night.
I really hope this gets fixed, or I will have to go for another checklist app.
Thanks for any help. Tom. PS: I really struggle to find out where “Preferences” can be found in the app. Any hint?

Issue identified. I was testing out the free version. It turns out the free plan does not support split screen. Nor does it have access to the “Preferences” menue. The workaround for folks like me who want to explore before purchasing a Pro plan is to tick of “Preview Pro-plan”. The you get 20 min to explore. Can be done several times.