public static function registerFatal()
    {
        Pool::createPool();

        // Disabled?
        if (static::$pool->config->getSetting(Fallback::SETTING_DISABLED) ||
            Config::$disabledByPhp
        ) {
            return;
        }

        // Wrong PHP version?
        if (version_compare(phpversion(), '7.0.0', '>=')) {
            static::$pool->messages->addMessage('php7');
            // In case that there is no other kreXX output, we show the configuration
            // with the message.
            static::editSettings();
            return;
        }

        static::$pool->createClass('Brainworxx\\Krexx\\Controller\\ErrorController')
            ->registerFatalAction();
    }