Getting PHP error when trying to bind to onEditionChange event
Because that particular event is raised from AppBehavior (and therefore WebApp), it doesn't follow the same component.eventName syntax that the other Craft events use and you can't use craft->on() to register to listen to it.

You can register to listen to it through the traditional Yii method, though.  This should work for you:

craft()-&gt;onEditionChange = function (Event $event) {
    craft()-&gt;womb-&gt;sendEvent($event);
};