Java 17 is used as of the Sonarqube 10.0 compatible build (v1.15.0) but has to produce Java 11 class files to remain compatible with anyone using older Sonar scanner versions.
Every time I open BTD6 I get this. I just installed melon loader into the BTD6 file and put the dll and xml mod helper files in the mod file but now I always get this and don't know what to do.