Upgrading 4.00 to 4.10

list of Changes made in 4.10 updation

CustomerID Replace with CustomerGUID. It means now in webAPI request you need to pass CustomerGUID instead of CustomerID
APISecretKey moved from API header to body, So now for all request, APISecretKey need to pass in the body instead of API header.
For Guest Customer pass as "CustomerGUID":"00000000-0000-0000-0000-000000000000", so in the response it will generate the customner_ID for that guest customer.

For the checkout methods as we get the customer_ID after add the product into the cart from that customer_ID get the CustomerGUID and pass that CustomerGUID in to the parameter.