I just sent in a patch to fix this for the pypi importer, although ideally we'd want versioning support for all importers with a uniform syntax. I poked and prodded at the RubyGems API to see if it can do what PyPI can. It's unfortunately much more limited: API v1 provides a method for querying all versions of a gem [1] and v2 provides a method for querying specific versions of a gem [2], although neither of them provides information about dependency versions, so we can't rely on it for recursive imports (since it would try to import latest versions of all dependencies). There's a method that fetches dependency and versioning info for all versions of all given gems but (probably due to the verbosity of JSON/YAML) it's in binary Ruby serialisation format [3]. I can try to hack a parser that surgically extracts dependency info from a given gem version. What do you think? ELPA runs into a similar problem in that it provides tarballs/files for older versions but dependency info is only provided in the repo file. (MELPA tries to directly peg all packages to their respective Git repos' trunks.) I presume it's much simpler with the gnu importer, as it's only a matter of pointing the FTP fetch in the right direction, although I couldn't confirm it, as the gnu importer doesn't work for me since my ISP blocks PGP keyserver ports. I need to take a closer look at CRAN, CPAN, TeXLive and opam. -- Lulu [1]: https://guides.rubygems.org/rubygems-org-api/#gem-version-methods [2]: https://guides.rubygems.org/rubygems-org-api-v2/ [3]: https://guides.rubygems.org/rubygems-org-api/#misc-methods