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Re: MIME-Version (Was Re: gzip-8bit)

2003-04-18 17:22:56

The problem with a version number change is that existing clients won't know
how to handle a message with version != 1.0.  So yes, you could change the
version number, but only if you're willing to completely abandon compatibility
with the installed base (and we weren't willing to do that even when we
introduced MIME).  

The value of the version number would be in allowing new clients (that
understood the both the old and new version of MIME) to be able to distinguish
version x messages from version y messages.  

To take an example from a slightly different field:  IPv4 and IPv6 both have
the IP version number in the first four bits of the packet, so if you have a
situation where IPv4 and IPv6 can both appear in the same context, then you
can tell the two apart.  (I don't think this actually happens in practice
unless you're tunneling IP over IP; for instance, both Ethernet and PPP have 
separate packet types for IPv4 and IPv6.) 

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