Fatal error: Uncaught Error: Class "WP_Upgrader_Skin" not found in /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/pdf-embedder/deprecated/install_skin.php:8 Stack trace: #0 {main} thrown in /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/pdf-embedder/deprecated/install_skin.php on line 8