Fatal error: Uncaught Error: Class 'WP_Widget' not found in H:\root\home\agubski-002\www\alexgubski\blog\wp-includes\widgets\class-wp-widget-categories.php:17 Stack trace: #0 {main} thrown in H:\root\home\agubski-002\www\alexgubski\blog\wp-includes\widgets\class-wp-widget-categories.php on line 17