do CPAN authors know the minimum perl required for their modules?

I would hope so. But what they might not know is the minimum Perl version for all of their prerequisite modules. But if each module knows a) its minimum version and b) all of its prereqs, then something like CPANPLUS (or, perhaps, CPANTS) could walk the tree and tell you if one of your prereqs needs a more recent version that the one that your are currently reporting.

What about old modules such as Net::Telnet will anyone release a new version of it just to include the META.yml

Maybe if it became a kwalitee measure :-)

do CPAN authors know the minimum perl required for their modules?

I would hope so.

Really? It seems like kind of a lot to ask every CPAN author. Maybe I'm missing something, but I can think of two ways one would know the minimum version of perl required for their module:

1. Know the details of each perl version well enough to predict what features their code uses will break and when those features appeared
2. Try their module out on each successive old version until they reach one that breaks

Neither of which seem like viable options for the majority of CPAN contributors. Now, I would hope most authors know at least one version that their module works on -- that is, the version it was developed against. But that is not the minimum version.

On further reflection I think you're probably right. I realised that I couldn't really tell you which version of Perl any of my modules need. I think I insist on 5.6 for most of them - but that's because I use "our" and "use warnings".

Perhaps it would be useful if we had a list of the features that were added in each version of Perl. I don't mean just dumping the contents of the delta files, but something a bit higher level. Does anyone know of anything like that?

--
<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg