Both X.400 and Usenet News have functions to correct messages
which you have sent by mistake.
In Usenet News, you can use the "cancel" command to remove
a message you have sent by mistake. You can then send a new
message with the replacement text.
In X.400, you can send a new message with an "obsoletes"
reference to a message to be replaced. "obsoletes" has
the same syntax as "In-Reply-To".
Presumably, you might cancel a message in x.400 by obsoleting
it with an empty message.
It is not clear to me whether Internet mail has a standard
for this facility or not.
It might be possible to claim that Internet mail does
have this facility. The reason for this is that RFC 1327
defines an "Obsoletes" RFC 822 heading field, with similar
syntax as for "In-Reply-To". This is defined by RFC 1327 in
order to map the X.400 facility to Internet mail in Gateways
from X.400 to Internet mail.
Question 1: Does this definition i RFC 1327 mean that the
"Obsoletes:" mail heading field is only standardised in
Internet mail for use by gateways from X.400? Or does it
mean that this heading field can be used also in communication
between Internet mail clients where X.400 is not involved?
My personal hope is that the answer to this question is that
this feature is also for general Internet mail usage.
If this is the case, my second question is:
Question 2: Are designers of Internet mail message systems
aware that Internet mail has an "Obsoletes:" heading field
so that they can include it in their message systems.
If not, what can be done to make them aware of this?
My personal experience is that this feature is ***very***
useful and ***much*** needed.
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Jacob Palme E-mail: jpalme(_at_)dsv(_dot_)su(_dot_)se
Phone: +46-8-664 77 48 or +46-8-16 16 67
Department of Computer and Fax: +46-8-664 77 48 between 9 am & 2 pm WET
Systems Sciences (DSV) Postal address: Skeppargatan 73,
Stockholm University S-11530 Stockholm, Sweden