Stability of valid IDN labels

Andrew Sullivan ajs at
Tue Apr 22 20:11:12 CEST 2008

On Tue, Apr 22, 2008 at 06:57:29PM +0200, Patrik Fältström wrote:

> timing, how heavy the process is etc. But, I need to correct one small 
> thing. We have in the tables document a special "Backwards compatibility 
> list" that works exactly like the exception list, but is a different (now 
> empty) table. This so developers very clearly can see what are the "kind 
> of" overrides that are made for this specific reason.

I like this feature, although I confess I was previously somewhat
confused about exactly what it was supposed to do.  Relevant to the
present thread, it seems to me that having this list is approximately
equivalent to the commitment that once a code point (or, I guess more
appropriately, code point plus context) has been valid, it can remain
so.  (I note that that isn't a MUST, but I am leery of making such a
strong statement about the future anyway.)  So the original concern is

Sorry for the noise, and thanks.


Andrew Sullivan
ajs at
+1 503 667 4564 x104

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