I was wondering whether it would make sense to offer 'zsync' download support for the release (and release candidate) ISO files.
Sure it is rare that Robert re-releases an ISO file (e.g. to quickly fix a small oversight instead of a X.Y.Z to a X.Y release), which would be the prime reason to use 'zsync' (i.e. to implement an efficient download of only the content of a file which is not already known). But it might still make sense to also offer 'zsync' downloads for the ISO files (in addition to all extensions).
I was wondering this, as I just did my v3.8.1 downloads (for Tiny and Multi) after cloning the v3.8 ISO files and then downloading the v3.8.1 ones via 'rsync' (so I'm aware of an alternative to my suggestion). I just thought that offering 'zsync' would be better as I understand it to be less demanding on the server (as AFAIK the client has to figure out the differences). In particular considering the size of MultiCore and the fact that the deltas between versions might be pretty small all this might help a little bit to limit the demands on our mirrors.