Hi, The *.class parameters was removed from symfony. https://github.com/symfony/framework-bundle/commit/3777050007e7dfef257087ef1f954a8cc7c27883 because of that the example related to overriding the translator class not working anymore in symfony3. ``` # app/config/config.yml parameters: translator.class: Acme\HelloBundle\Translation\Translator ``` http://symfony.com/doc/current/bundles/override.html