I don’t know about you but I haven’t used a FAX in years. When I joined IBM I signed up for a eFax account but never used it. It was hard to come to terms with it at the start as my previous employment prior to University was an Architectural practice, where the FAX was king.
Any document that you want to send these days is just pdf’d and then attached and sent soft copy.
More recently IBM’s phone system was updated to allow you to receive Faxes on your landline number and stored, allowing you to redirect them to your nearest fax machine which was pretty neat, but again, didn’t use that either.
So my answer to WWD’s question is yes, dump the FAX number.