We are a bit confused as our nice auto-generated invoice numbers have suddenly stopped working. We have reached invoice 9 and the system has now jumped down to 0, and no longer generates anything else but 0 automatically.
It just gets picked up from the last invoice raised. So now if you raise a new invoice on your account you will see something like this:
If you changed the invoice number manually to say KFDS00013, the next time you raise an invoice it will show as KFDS00014. The system always tries to increment from the last invoice raised.