Incompatibility with PHP 8.0+

We upgraded the Webserver from PHP 7.4 to PHP 8.3 this week and the following error was created:

2024-05-09T08:58:43+00:00 Critical Uncaught TypeError: stripslashes(): Argument #1 ($string) must be of type string, array given in /var/www/clients/client1/web1/web/prod/wp-content/plugins/woocommerce-wholesale-pricing/inc/class-wwp-wholesale-frontend.php:44  
Additional context
{
    "error": {
        "type": 1,
        "file": "\/var\/www\/clients\/client1\/web1\/web\/prod\/wp-content\/plugins\/woocommerce-wholesale-pricing\/inc\/class-wwp-wholesale-frontend.php",
        "line": 44
    },
    "backtrace": [
        "",
        "#0 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-content\/plugins\/woocommerce-wholesale-pricing\/inc\/class-wwp-wholesale-frontend.php(44): stripslashes()",
        "#1 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/class-wp-hook.php(324): Wwp_Wholesale_Pricing_Frontend->wwp_after_checkout_validation()",
        "#2 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/class-wp-hook.php(348): WP_Hook->apply_filters()",
        "#3 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/plugin.php(517): WP_Hook->do_action()",
        "#4 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-content\/plugins\/woocommerce\/includes\/class-wc-checkout.php(961): do_action()",
        "#5 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-content\/plugins\/woocommerce\/includes\/class-wc-checkout.php(1257): WC_Checkout->validate_checkout()",
        "#6 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-content\/plugins\/woocommerce\/includes\/class-wc-ajax.php(520): WC_Checkout->process_checkout()",
        "#7 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/class-wp-hook.php(324): WC_AJAX::checkout()",
        "#8 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/class-wp-hook.php(348): WP_Hook->apply_filters()",
        "#9 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/plugin.php(517): WP_Hook->do_action()",
        "#10 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-content\/plugins\/woocommerce\/includes\/class-wc-ajax.php(96): do_action()",
        "#11 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/class-wp-hook.php(324): WC_AJAX::do_wc_ajax()",
        "#12 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/class-wp-hook.php(348): WP_Hook->apply_filters()",
        "#13 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/plugin.php(517): WP_Hook->do_action()",
        "#14 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-includes\/template-loader.php(13): do_action()",
        "#15 \/var\/www\/clients\/client1\/web1\/web\/prod\/wp-blog-header.php(19): require_once('...')",
        "#16 \/var\/www\/clients\/client1\/web1\/web\/index.php(17): require('...')",
        "#17 {main}",
        "thrown"
    ]
}

Disabling the plugin removed the error.
We reenabled the plugin and went back to PHP 8.0, the error still existed. Going back to PHP 7.4 fixes the problem.

This is a security issue and needs resolving.