Fatal error: Uncaught Error: Call to undefined function add_filter() in /home/kacperg/public_html/kacpergr/wp-content/plugins/modula-best-grid-gallery/includes/class-modula-backward-compatibility.php:12 Stack trace: #0 /home/kacperg/public_html/kacpergr/wp-content/plugins/modula-best-grid-gallery/includes/class-modula-backward-compatibility.php(275): Modula_Backward_Compatibility->__construct() #1 {main} thrown in /home/kacperg/public_html/kacpergr/wp-content/plugins/modula-best-grid-gallery/includes/class-modula-backward-compatibility.php on line 12