Hello all,

As detailed earlier ('\tl_to_(lower|upper)case:n - Generating char
tokens', http://article.gmane.org/gmane.comp.tex.latex.latex3/3667
onward), the team have for some time been keen to deprecate
\tl_to_(lower|upper)case:n. Following work both by the team and by third
parties, we are now ready to do this. (Many thanks to package authors
for their engagement in this process.)

The next expl3 snapshot to CTAN (to go this weekend) will therefore
deprecate

- \tl_to_lowercase:n
- \tl_to_uppercase:n

with replacement functions depending upon the operation involved:

- For generation of 'unusual' character tokens, \char_generate:nn
- For case changing text, \tl_(lower|upper)_case:n(n)
- For case folding (caseless tests), \str_fold_case:n
- For programming string case changing (e.g. generating csnames
  on-th-fly), \str_(lower|upper)_case:n

Regards,

Joseph