Unicode 5.2 -> 6.0

[Nicolas Williams]

To restate my other reply more concisely:

a) the UC allows for grandfathering in the case of U+19CA;

b) I can't find any way to render U+19CA;

c) if we can't find a way to render U+19CA then we should assume U+19CA
   is not used in domainname labels anywhere and adopt the otherwise
   backward compatibility breaking PVALID->DISALLOWED change.

d) if we can find a way to render U+19CA then we need more information
   but should default to grandfathering U+19CA, per-(a).

Cheers,

Nico
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