Erro do plugin no PHP 8

Quando uso seu plugin no PHP 8, recebo esse erro fatal várias vezes:

2022-09-03T12:42:19+00:00 CRITICAL Uncaught TypeError: Unsupported operand types: int * string in /www/siteab_581/public/wp-content/plugins/woo-shipping-gateway/includes/class-wc-frenet.php:471
Stack trace:
#0 /www/siteab_581/public/wp-content/plugins/arti-marketplace-frenet/includes/classes/class-arti-frenet-marketplace.php(43): WC_Frenet->frenet_calculate(Array, 'JSON')
#1 /www/siteab_581/public/wp-content/plugins/woo-shipping-gateway/includes/class-wc-frenet.php(309): Arti_Frenet_Marketplace->frenet_calculate(Array, 'JSON')
#2 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-shipping-method.php(233): WC_Frenet->calculate_shipping(Array)
#3 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-shipping.php(348): WC_Shipping_Method->get_rates_for_package(Array)
#4 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-shipping.php(260): WC_Shipping->calculate_shipping_for_package(Array, 3)
#5 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-cart.php(1420): WC_Shipping->calculate_shipping(Array)
#6 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php(339): WC_Cart->calculate_shipping()
#7 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php(850): WC_Cart_Totals->get_shipping_from_cart()
#8 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php(144): WC_Cart_Totals->calculate_shipping_totals()
#9 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php(134): WC_Cart_Totals->calculate()
#10 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-cart.php(1398): WC_Cart_Totals->__construct(Object(WC_Cart))
#11 /www/siteab_581/public/wp-content/plugins/woocommerce/includes/class-wc-cart-session.php(179): WC_Cart->calculate_totals()
#12 /www/siteab_581/public/wp-includes/class-wp-hook.php(307): WC_Cart_Session->get_cart_from_session('')
#13 /www/siteab_581/public/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters(NULL, Array)
#14 /www/siteab_581/public/wp-includes/plugin.php(476): WP_Hook->do_action(Array)
#15 /www/siteab_581/public/wp-settings.php(620): do_action('wp_loaded')
#16 /www/siteab_581/public/wp-config.php(98): require_once('/www/siteab_58...')
#17 /www/siteab_581/public/wp-load.php(50): require_once('/www/siteab_58...')
#18 /www/siteab_581/public/wp-admin/admin-ajax.php(22): require_once('/www/siteab_58...')
#19 {main}
  thrown, em /www/siteab_581/public/wp-content/plugins/woo-shipping-gateway/includes/class-wc-frenet.php, na linha 471

Gostaria de saber como isso pode ser corrigido, pois os servidores est?o abandonando o PHP 7.4 até o final do ano.