Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($function) must be a valid callback, non-static method wp_posts_filter::wppf_init() cannot be called statically in /var/www/0/210213/www/wp-includes/class-wp-hook.php:288 Stack trace: #0 /var/www/0/210213/www/wp-includes/class-wp-hook.php(312): WP_Hook->apply_filters(NULL, Array) #1 /var/www/0/210213/www/wp-includes/plugin.php(478): WP_Hook->do_action(Array) #2 /var/www/0/210213/www/wp-settings.php(523): do_action('init') #3 /var/www/0/210213/www/wp-config.php(96): require_once('/var/www/0/2102...') #4 /var/www/0/210213/www/wp-load.php(37): require_once('/var/www/0/2102...') #5 /var/www/0/210213/www/wp-blog-header.php(13): require_once('/var/www/0/2102...') #6 /var/www/0/210213/www/index.php(17): require('/var/www/0/2102...') #7 {main} thrown in /var/www/0/210213/www/wp-includes/class-wp-hook.php on line 288