>Then, HTTrack can handle this automatically 
>("update a mirror"). Some servers may respond 
>wrongly to the refresh request, however.

If the server says a change has happened even though 
it didn't, that is not efficient but not a big deal.\

However, do you know if a server might respond 
that 'no change has happened' even though a file was 
changed? If so, this could be a big problem (not 
updating changed files on an update). So, do you know 
of anything that could be done using HTTrack to very 
reliably get changed files (besides downloading 
everything each time)?
I would be willing to spend some time on this, 
including changing the code if need be, even adding it 
as a command-line option and sending the changes to 
you for your approval. Just wondering if any you have 
any hints.

many thanks for a truly great piece of software, 
and even more thanks for providing the source,
john