IDNA2003 complication (was: Re: Changing the xn-- prefix)

Andrew Sullivan ajs at
Thu Mar 27 17:11:09 CET 2008

On Thu, Mar 27, 2008 at 11:38:10AM +0900, Martin Duerst wrote:

> Can you give some details on what you mean by IDNA2003 complication?

Roughly, "All the things that the proposed WG seems to think it is

> I very much hope that we can fix IDNA2003 where it needs fixing, but
> I don't see, based on the current proposals, that overall, for an
> application programmer or for a registrant, things would get simpler
> with IDNAbis.

I agree.  But a proposal that we do _both_ IDNA200x and IDNA2003 means
that you have two sets of complications.  And they're disjunct.  For
instance, on the one hand, as a developer or operator aiming at
IDNA2003 conformance, I have to find some way of keeping around
ancient unicode libaries; whereas as a developer or operator aiming at
IDNA200x conformance, I have to worry about Unicode updates to make
sure my application accommodates them.  As an operator under ICANN
with an IDNA2003 system, I have to work out rules with various
language authorities (and finding the right one is a minefield all its
own) about what code points are in or out; whereas as an operator
attempting to conform with IDNA200x, national-language-authority
confusion may get solved (I'm actually pretending to be sanguine about
that; I confess that in reality I'm not quite so hopeful), because
there's an algorithm that determines the Internationalized-LDH-analogue.

I argue that, given that we already have strong reason to believe that
IDNA2003 is going to be deprecated, it would be a very bad idea to
specify it as some sort of minimally compatible protocol.  If you do
that, people will implement to the minimum.  I think it was John
Klenisn said in the BOF that, if we cannot accept that there will be
some possibly irritating backwards incompatibilities, we might as well
just stop immediately.  I think the corollary is that we cannot
specify a backwards compatibility criterion, or all we'll ever get is
that backward compatibility, because the cost of keeping around
two somewhat incompatible protocols is too high.

Best regards,
Andrew Sullivan
ajs at
+1 503 667 4564 x104

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