Fatal error: Uncaught Error: Class "Composer\Installer\LibraryInstaller" not found in /usr/local/www/wordpress/wp-content/plugins/.old/sitepress-multilingual-cms-/vendor/composer/installers/src/Composer/Installers/Installer.php:13 Stack trace: #0 {main} thrown in /usr/local/www/wordpress/wp-content/plugins/.old/sitepress-multilingual-cms-/vendor/composer/installers/src/Composer/Installers/Installer.php on line 13