Standardizing on IDNA 2003 in the URL Standard

Jungshik Shin (신정식, 申政湜) jungshik at
Fri Jan 31 00:01:21 CET 2014

2014-01-16 Anne van Kesteren <annevk at>

> On Thu, Jan 16, 2014 at 11:36 AM, Gervase Markham <gerv at>
> wrote:
> > On 16/01/14 11:17, Anne van Kesteren wrote:
> >> It's not worse if it's fully backwards compatible and mostly
> >> interoperable across all major clients. At that point the standard is
> >> just wrong.
> >
> > And having a standard fixed to Unicode 3.2 is not also "just wrong"?
> The point is that in practice, it isn't fixed to Unicode 3.2. I have
> yet to encounter an IDNA2003 implementation that does that. It turns
> out the setup we have in practice is a compatible evolution.

ICU's IDNA 2003 implementation just does that. Before Chrome switched to
UTS 46 a few milestones ago, that's what's used by Chrome.

And, Safari is likely to still use that (well, it depends on Mac OS X's
network API so that its behavior may differ on different OS X/iOS's).


> > And I refer you to my comments above. Problems like lowercasing (for
> > better or worse) are punted by IDNA2008 and are labelled as an
> > application-level problem. In practice, what everyone should do for best
> > interoperability is implement the same application-level mappings, and
> > implement ones which are as compatible as possible with IDNA2003.
> > Hence.... UTS46.
> I think I did mention earlier on UTS46 might be okay, depending on the
> details. I am hoping to hear from Mark on the matter.
> --
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