Feature implemented by scanning the existing files before creating the content of index.html. It should be sufficient.
Manually added releases will be lost during the next mirroring if not asked again.
Example:
$ ./pypim.py -a pyxb==1.2.3
downloads PyXB version 1.2.3 (an old version) and the 3 most recent versions.
$ ./pypim.py -a pyxb
downloads the 3 most recent versions. The old one, although present in the mirror, will not be referenced in index.html.
See previous topic. The inconvenient is that mirror will always grow.
When a release becomes too old, it won't be listed in index.html. And not deleted from disk.
Command-line option --remove-orphans.
If a previously downloaded file is removed from a release, it will remain in the mirror.