The app is designed to work with or without root access. Root access is recommended on Android 7 and later, because Android 7 adds some fairly draconian restrictions on the ability for a user to see what is running on his/her device.
SystemPanel 2 is not being distributed as an upgrade to the original SystemPanel. You can even have both versions on your device at the same time. Version 2 no longer uses a pay to unlock all features revenue model. All features are free. It has native ads, and you can pay a couple of bucks to remove them permanently. The ads are intended to blend into the UI so they aren’t distracting, they don’t animate, and they don’t annoy.
SystemPanel 2 v2.0.b4 Apk