Q2: What mapping function should be used in a revised IDNA2008specification?

[Harald Alvestrand]

Alexander Mayrhofer wrote:
> (again, sorry for the late reply, and potentially ignorance for any
> discussion that i missed) 
>
>   
>> What characters should be mapped into what other characters in a  
>> revised IDNA2008 specification?
>>     
>
> I'm speaking from a perspective of a registry primarily using german
> script. Therefore, we're primarily concerned about case folding, which
> should be covered by standard Unicode case folding tables. We have
> issues with the "sz" "sharp s" problem, because the "sharp s" appears in
> many german words, but that's a problem that we share with our esteemed
> german colleagues.
>   
Alexander,
for precision:

I've seen 3 variants of the position on mapping "A" to "a".....

1 - casefolding (UTR#21 section 2.3 paragraph following S.3) is required
2 - lowercasing (UTR#21 section 2.3 bullet S.2) is the one that's 
required, but casefolding is OK if others prefer it
3 - lowercasing is required, casefolding is harmful and should be avoided.

Which is your preference?

               Harald