KioskBuddy only supports iOS at this time, so the largest screen size you can use is the 12.9 inch iPad Pro variety which some of our users use. Any iPad model will work as long as it can run iOS 11 or higher. You can use this article from Apple as a reference for which models those are: https://support.apple.com/en-us/HT209574
We're beta testing KioskBuddy on Android. You can take part in this beta test by downloading the beta version of the app here: https://play.google.com/store/apps/details?id=com.kioskbuddy