@Version marks a config class with a version integer. This can be used for simple record-keeping, of course, or used to handle potentially breaking updates in a meaningful manner. The version is marked at the top of the .toml file (0 by default) and the serialized version is compared against an annotated version integer, if any. If a mismatch is detected, the configs update() method is called for mismatch handling.

@Version(version = 1)
public class MyConfig extends Config {
    //constructor goes here
    
    @Override
    public void update(int deserializedVersion) {
        if (deserializedVersion < 1) {
            //do stuff to fix potential issues.
        }
    }
}