Nice to have you join this thread, @daveGum. I've got some additional information about this feature in QuickBooks Online.

We see how this feature can be beneficial to you and your business. However, as provided by my colleagues above, the convenience fee is only a beta feature of the QuickBooks Online program. That said, there's no official document, as it was a business decision to discontinue the beta feature.

Also, please see the screenshot below for the reference of the old feature:

In addition, you might consider checking out this article in case you might want to consider manually entering service fees to invoices: Manually add service fees to invoices in QuickBooks Online.

I'm always ready to assist you if you have any other questions about managing invoices or QBO-related concerns. Tag me in your reply, and I'll sprint back into action. Have a good one, and keep safe.