namespace App\EventListener;

use App\Entity\User;
use Doctrine\Common\Persistence\Event\LifecycleEventArgs;

class UserChangedNotifier
{
    public function __invoke(User $user, LifecycleEventArgs $event)
    {
        // ...
    }
}

services:
  # ...

  App\EventListener\UserChangedNotifier:
    tags:
      - name: "doctrine.orm.entity_listener"
        entity: 'App\Entity\User'
        # before, when not defining the method name, Symfony looked for
        # a method called after the event (e.g. 'postUpdate()') Now it
        # will also look for an '__invoke()' method
        event: "postUpdate"