Stability of valid IDN labels

Patrik Fältström patrik at
Tue Apr 22 07:17:58 CEST 2008

On 22 apr 2008, at 07.15, Patrik Fältström wrote:

> On 21 apr 2008, at 22.20, Andrew Sullivan wrote:
>> So for practical purposes, isn't it enough to say, "Once a character
>> is valid, it is valid forever," irrespective of whether it is in fact
>> ever registered?
> Personally I see it much much more rigid. Once a character have been  
> assigned in Unicode it will by definition get a derived property  
> value due to the algorithms defined in the IDNA200X documents. That  
> value can never change.
> The original design team from the origin had a proposed "MAYBE"  
> category, but the consensus on this mailing list was to remove it.  
> And that created the situation that once a property value is  
> calculated on an assigned codepoint, it can not change.

Oh, let me add one thing: RFCs can always be rewised, and if something  
really has to change, of course the RFCs and the algorithm can be  
completely obsoleted and changed and whatever.

But, the big change in the work regarding IDNA200X was that we  
originally had MAYBE category, from which codepoints could be moved,  
but that is now removed from the design.


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