Change WooCommerce default password security level

The only existing hook setting for that is woocommerce_min_password_strength filter hook. So you can set a custom hook function and lowering this strenght. There is 4 possible settings:

• 3 => Strong (default)
• 2 => Medium
• 1 => Weak
• 0 => Very Weak (anything).

Here is that code:

add_filter( 'woocommerce_min_password_strength', 'reduce_min_strength_password_requirement' );
function reduce_min_strength_password_requirement( $strength ) {
    // 3 => Strong (default) | 2 => Medium | 1 => Weak | 0 => Very Weak (anything).
    return 2; 
}

Code goes in function.php file of your active child theme (or theme) or also in any plugin file.

This code is tested and works.

All other solutions will be complicated and a real development.

You should try woocommerce_update_cart_action_cart_updated action hook. I have revisited your code a bit. Try this:

add_action( 'woocommerce_update_cart_action_cart_updated', 'on_action_cart_updated', 20, 1 );
function on_action_cart_updated( $cart_updated ){

    $applied_coupons = WC()->cart->get_applied_coupons();

    if( count( $applied_coupons ) > 0 ){
        $new_value        = WC()->cart->get_cart_subtotal();
        $discounted       = WC()->cart->coupon_discount_totals;
        $discounted_value = array_values($discounted)[0];
        $new_value        = $new_value-$discounted_value + 100;

        WC()->cart->set_total( $new_value );

        if ( $cart_updated ) {
            // Recalc our totals
            WC()->cart->calculate_totals();
        }
    }
}

Code goes in function.php file of your active child theme (or active theme). Untested. It could work.

Update: The WC_Cart set_total_price() method doesn't exist… I have replaced it by existing WC_Cart set_total()

Updated: The code that you found in Github is outdated, clumsy and complicated, since there is a dedicated filter hook now. You should better try this lightweight and effective code, that will set the default order status for "Cash on delivery" payment gateway (COD) to "On Hold":

add_filter( 'woocommerce_cod_process_payment_order_status', 'change_cod_payment_order_status', 10, 2 );
function change_cod_payment_order_status( $order_status, $order ) {
    return 'on-hold';
}

Code goes in functions.php file of your active child theme (active theme). Tested and works.

So the default order status set by the payment gateway is now "On Hold" instead of "Processing"