CMS-X.400: [application/x400-content] versus [application/x400-bp ]

Hello,

There was some discussion early this year about the proposed new MIME 
subtype "application/x400-content".

Have there been any further discussions and/or decisions on this topic? 
The mailing list contains only the initial few exchanges.

Was the application/x400-bp type (IANA-registered by RFC 1494) not 
considered? At first glance, this does look like it could encapsulate 
ForwardedContent. What were the reasons for proposing a new MIME type?

Best Regards,
                Hari.