Eszett and IDNAv2 vs IDNA2008

Andrew Sullivan ajs at
Thu Mar 12 13:56:27 CET 2009

On Thu, Mar 12, 2009 at 01:28:17AM +0000, Shawn Steele (???) wrote:

> I think that this summarizes some of my thinking as well.  Any
> implementation of IDN (at least at the browser level) will need to
> be backward compatible with IDNA2003. 

Do you mean that really, or do you mean, "Initially, any
implementation. . . "?  This is a practical difference between "transition
strategy" and "being backward compatible" that I think John has been
talking about.  

If what you're saying is that backward compatibility will be necessary
while zones switch from IDNA2003 to IDNA2008 behaviour, I agree (and I
can see there are lots of ways that could fail to work).  It probably
means the various try-2008-fail-to-2003 strategies people have talked
about, which includes the two-lookup approach.  (That two-lookup
approach is indeed broken in principle, but it might be good enough
for a transition strategy.)

If what you're saying is that IDNA2003 is around forever, then how do
you deal with John's argument that, if you mean that, IDNAv2 won't
solve the problem either.


Andrew Sullivan
ajs at
Shinkuro, Inc.

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