> Something major changed in libcurl between 7.21 and 7.24 and I need to
> fallback and of course, don't have A16 any longer.

   I know nothing, but _assuming_ that you're right about this major
change, ...

   Can you build your own from the sources?  I see oodles of old cURL
kits at http://curl.haxx.se/download/ , including 7.21 (actually,
several 7.21.x), plus some newer-than-7.24 kits.