Fatal error: Uncaught Error: Call to undefined function add_filter() in /home/kacperg/public_html/kacpergr/wp-content/plugins/modula-best-grid-gallery/includes/update/class-modula-update.php:22 Stack trace: #0 /home/kacperg/public_html/kacpergr/wp-content/plugins/modula-best-grid-gallery/includes/update/class-modula-update.php(74): Modula_Update->__construct() #1 /home/kacperg/public_html/kacpergr/wp-content/plugins/modula-best-grid-gallery/includes/update/class-modula-update.php(130): Modula_Update::get_instance() #2 {main} thrown in /home/kacperg/public_html/kacpergr/wp-content/plugins/modula-best-grid-gallery/includes/update/class-modula-update.php on line 22