name and filename parameters

Question about composing a MIME part where I would suggest
also the file name.

Question:
In the case that I would suggest a file name to the remote
MIME client could I use only the name parameter of the content-type
or MUST I add the content-disposition header with the filename parameter?

My doubt come also from the following sentence in RFC3851
(Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1
                         Message Specification):

.. ..... .
3.2.1.  The name and filename Parameters

   For the application/pkcs7-mime, sending agents SHOULD emit the
   optional "name" parameter to the Content-Type field for compatibility
   with older systems.  Sending agents SHOULD also emit the optional
   Content-Disposition field [CONTDISP] with the "filename" parameter.
   If a sending agent emits the above parameters, the value of the
   parameters SHOULD be a file name with the appropriate extension:
 .... ..... ... 

where a system using only the name parameter is considered an "old system".
So, I don't understand if "old system" is related to some old S/MIME
system, or to a generic old MIME system....

Francesco