Text index v3 supports case folding for Unicode's 'C', 'S', and 'T' mappings (see ftp://ftp.unicode.org/Public/UNIDATA/CaseFolding.txt), which are all one character to one character.

There are about 100 'F' mappings where a character will case fold to more than one character. This includes the latin sharp s (ß) which case folds to "ss".

To support these there needs to be an additional pass when lowercasing a unicode::String that supports expanding the resulting string.