Error: Uncaught Error

Hi there,
just tested the plugin with one label (stock status: in stock). But it dos not work but shows the following error message. Any Idea? Latest WordPress and DIVI. Thx a lot.

Fatal error: Uncaught Error: Call to protected method WC_Product::get_availability_text() from context ‘BeRocket_products_label’ in /home/citipost/public_html/schwerin/wp-content/plugins/advanced-product-labels-for-woocommerce/main.php:549 Stack trace: #0 /home/citipost/public_html/schwerin/wp-content/plugins/advanced-product-labels-for-woocommerce/main.php(433): BeRocket_products_label->show_label_on_product(Array, Object(WC_Product_Simple)) #1 /home/citipost/public_html/schwerin/wp-content/plugins/advanced-product-labels-for-woocommerce/main.php(373): BeRocket_products_label->set_label() #2 /home/citipost/public_html/schwerin/wp-includes/class-wp-hook.php(286): BeRocket_products_label->set_all_label(”) #3 /home/citipost/public_html/schwerin/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #4 /home/citipost/public_html/schwerin/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #5 /home/citipost/public_html/schwerin/wp-content/plugins/woocommerce/templates/content-product.php(42): do_action(‘w in /home/citipost/public_html/schwerin/wp-content/plugins/advanced-product-labels-for-woocommerce/main.php on line 549