Fatal error: Uncaught Error: Interface "Composer\Plugin\PluginInterface" not found in /usr/local/www/wordpress/wp-content/plugins/.old/sitepress-multilingual-cms/vendor/composer/installers/src/Composer/Installers/Plugin.php:9 Stack trace: #0 {main} thrown in /usr/local/www/wordpress/wp-content/plugins/.old/sitepress-multilingual-cms/vendor/composer/installers/src/Composer/Installers/Plugin.php on line 9