Duplicate Transaction ID and solution

Thank you for reaching out to us. I have submitted a message to the developers to investigate further your request.

Kind regards.

Thank you. We will add an option for it.

We have added a settings option for this in the latest version of the addon. Let me know if this works for you.

How does it come up with the unique invoice ID? would it be possible to just add a field in the settings, so we can enter our custom inv. id prefix?

It generates a unique ID to use as the prefix. Using a static string would not ensure uniqueness.

The addon includes a filter hook that allows you to customize the prefix to suit your needs, rather than using the new option in the addon.

See the following page for code example on this:

https://wp-ecommerce.net/paypal-pro-payment-gateway-for-woocommerce#wcpproginvnumwooordernumber