Support not-allowed attachments notice
I was directed by support that this would be a great feature request.
I have a lot of clients that use email instead of the WHMCS system for support. Normal because email is so much easier for them :)
When a client sends an email with an unsupported attachment type (say .html), it would be great to have an automated reply that their email contains invalid attachments. Simple but, effective. Enough of those and the client should get the point.