ObserverMethod.notify(T event, Set<Annotation> qualifiers) has been added post CDI 1.0 as part of CDI-36.

The added method breaks backwards compatibility (an existing 1.0 Extension may be registering an ObserverMethod implementation that would not implement that method, since it is not part of the 1.0 API).

We should probably isolate that method into a subinterface e.g.:

public interface CuriousObserverMethod<T> extends ObservetMethod<T> {

   void notify(T event, Set<Annotation> qualifiers);

}