How to set logger level?

I upgraded 3.16 to 4.1 and traccar service cannot start due to logger level.
I used to set logger level "warn" in 3.16 but in 4.1, I have to set logger level "warning" to get it work.
What about the other level?
Now I want to set logger level to "error" level but the value "error" just doesn't work.

You can find supported levels here:

https://docs.oracle.com/javase/8/docs/api/java/util/logging/Level.html

Thanks Anton!
You're the best :-)