Use APKPure App
Get My SuperUser old version APK for Android
♣ Hello! Check Your Root ♣
"Do i have root?"
This app will answer your question.
It will also give you a few details about your su binary,super user application and busybox.
Press the button and read the results.
Maybe share them afterwards.
This app will NOT root your DEVICE!
If this came preinstalled with your custom ROM, don't ask me how to uninstall it!