Fatal error: Uncaught Error: Class "WP_Widget" not found in /usr/local/www/wordpress/wp-content/plugins/yet-another-related-posts-plugin/classes/YARPP_Widget.php:3 Stack trace: #0 {main} thrown in /usr/local/www/wordpress/wp-content/plugins/yet-another-related-posts-plugin/classes/YARPP_Widget.php on line 3