Is it possible to password protect files for download by site visitors?
Yes, this is something we have planned for a future major release: version 5.1 (we are currently in version 4.5.7).
You can add a password protection to the files or categories when the feature is published.
Though it’s hard to give a precise date on new features release for various reasons.
It mainly depends on the development roadmap we've defined for the developer and problems we may encounter during this period