Fatal error: Uncaught Error: Call to undefined method WooCommerce::add_error() in /home/gunlaw/public_html/wp-content/plugins/woocommerce-incremental-product-quantities/includes/class-ipq-validations.php:104 Stack trace: #0 /home/gunlaw/public_html/wp-content/plugins/woocommerce-incremental-product-quantities/includes/class-ipq-validations.php(31): IPQ_Quantity_Validations->validate_single_product(true, 272, 1, false, NULL, NULL) #1 /home/gunlaw/public_html/wp-includes/class-wp-hook.php(324): IPQ_Quantity_Validations->add_to_cart_validation(true, 272, 1) #2 /home/gunlaw/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters(true, Array) #3 /home/gunlaw/public_html/wp-content/plugins/woocommerce/includes/class-wc-form-handler.php(870): apply_filters('woocommerce_add...', true, 272, 1) #4 /home/gunlaw/public_html/wp-content/plugins/woocommerce/includes/class-wc-form-handler.php(844): WC_Form_Handler::add_to_cart_handler_simple(272) #5 /home/gunlaw/public_html/wp-includes/class-wp-hook.php(324): WC_Form_Handler::add_to_cart_action('') #6 /home/gunlaw/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array) #7 /home/gunlaw/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #8 /home/gunlaw/public_html/wp-settings.php(749): do_action('wp_loaded') #9 /home/gunlaw/public_html/wp-config.php(115): require_once('/home/gunlaw/pu...') #10 /home/gunlaw/public_html/wp-load.php(50): require_once('/home/gunlaw/pu...') #11 /home/gunlaw/public_html/wp-blog-header.php(13): require_once('/home/gunlaw/pu...') #12 /home/gunlaw/public_html/index.php(17): require('/home/gunlaw/pu...') #13 {main} thrown in /home/gunlaw/public_html/wp-content/plugins/woocommerce-incremental-product-quantities/includes/class-ipq-validations.php on line 104