 Sometime during the evolution of Fido, file attachments were added to the system, allowing a file to be referenced from an email message.During the normal exchange between two instances of FIDONET, any files attached to the messages in the packets were delivered after the packet itself had been up or downloaded.It is not clear when this was added, but it was already a feature of the basic system when the 8 February 1985 version of the FidoNet standards document was released, so this was added very early in Fido's history.