FOX - WooCommerce Currency Switcher Professional

Plugin URL: https://yithemes.com/themes/plugins/yith-woocommerce-booking/

In file functions.php of the current wp theme add next code:

add_filter('yith_wcbk_get_price_to_display', function ($price) {

    if (class_exists('WOOCS') AND $price > 0) {
        global $WOOCS;
        $price = $WOOCS->woocs_exchange_value(floatval($price));
    }

    return $price;
});