stability

All,

This is probably well known to most of you, but the General Category 
Value in the Unicode Character Database and the stability of that value 
are not very relevant to IDNA, which does not depend on the Unicode 
Categories.

IDNA depends on the Unicode Normalization Form KC table, and there have 
been very few changes indeed in this table:

http://www.unicode.org/Public/UNIDATA/NormalizationCorrections.txt

Also, IDNA apps depend on tables for converting from various non-Unicode 
encodings to Unicode. This is another place where instability could 
affect lookups, potentially even in dangerous ways. Stringprep and IDNA 
already mention this issue in their Security Considerations sections.

Erik