Standardizing on IDNA 2003 in the URL Standard

Andrew Sullivan ajs at
Thu Aug 22 17:17:10 CEST 2013

On Thu, Aug 22, 2013 at 01:17:58PM +0100, Anne van Kesteren wrote:
> On Thu, Aug 22, 2013 at 12:38 PM, Mark Davis ☕ <mark at> wrote:

> > 2 Stay on IDNA2003.

> 2 as deployed is not stuck on an archaic Unicode version. 

Right.  2 as deployed instead has _new_ compatibility problems as new
registries and names compatible with IDNA2008 but that don't work
correctly under IDNA2003 come online.  Since that's where all the
growth in Unicode is, this position represents the trade off of
preventing a few things breaking right now (including a number of
names that are impossible to type, like those with smileys and so on)
at the cost of breaking future things more and more, as the IDNA2003
assumption of Unicode 3.2 shows more and more strain.

It seems to me that one possible explanation for the success of IPv4
was the early willingness to say, "These early ones didn't work.
We're breaking them, even if you're using them.  Sorry."  I very
strongly agree that preserving compatibility is extremely important.
But if you're going to have to break things -- and given what we've
learned, _some_ stuff needs to break -- the time to do it is as soon
as possible.  The problem will only be worse over time.



Andrew Sullivan
ajs at

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