Adding pdf attachment to messages

In my experience using Numista, several times I have to send pdf documents to swappers, and since only picture may be attached, I have either to take pictures of the various parts of the pdf or ask for an email
Could we add this possibility to the Numista messages?

I can’t think of any reason why you should be able to send PDF-files. Plus, how are you going to prevent corrupted files or files with exploits? I strongly advise against this.