Installed application

why the application that has been made is then installed on a different Android version, the results of the application that is installed are also different. there are errors and there are running smoothly.

Please elaborate


I made an application using kodular, then I mirrored it with Companion, the companion is on my cellphone with Android 8.1 version. then after my application was finished, I tried it on a cellphone that had an Android version higher than version 8.1 and the result was that there were several blank screens, but when I tried my application on an Adnroid cellphone version 8.1 my application ran well and was responsive. is there anyone who can help me? I am very troubled because of this problem.