well, that doesn't work either...
Response code : 400
Response body :
{"Error":[{"error_description":"The file you tried to upload has an invalid format, please choose another file and try again.","error_description_translated":"The file you tried to upload has an invalid format, please choose another file and try again."}]}
I'm wondering if it's caused by the default encoding of my system (OSX) or something. I'll have another look next week.
@Bunq. is there some sort of interface where we can just upload an attachment from there?