Which MIME type to use for a binary file that's specific to my program?

Question

My program uses its own binary file type, so I assume I can't use MIME type text/plain, as it is not a 7-bit ASCII file.

Should I just call it "application/myappname"?

user_761771 · Answer

According to the specification RFC 2045 #Syntax of the Content-Type Header Field application/myappname is not allowed, but application/x-myappname is allowed and sounds most appropriate for your application to me.