This is based on just reading the docs, I have not had a chance to dig deeply into using mod_perl / libapreq2 (yet).

From the documentation and the source, it appears that the module is a wrapper around libapreq2. If the interface / API has not changed from the Apache group, I am not certain that there would need to be a change to the wrapper. At most I would expect a recompile / relink. With a stable API, why would there be a need to update the glue part of the library?

Can I assume that you have set the MAX_BODY / POST_MAX parameters? It looks like, unless I am missing something, that those settings should allow you to upload larger files. It appears that 1M is the default setting.