Moose and Moo support Perl 5.8, but not 5.6. And we frequently see questions from people stuck with 5.8 on RHEL (and apparently unable/unwilling/forbidden from installing a newer local Perl). But it's quite unusual to find a CPAN tester still smoking distributions on Perl's that precede 5.6. Perl's newest features are fantastic for in-house code, but I believe CPAN code ought to be more portable.

I look at it this way; When I put something up on CPAN it's so that others might get some use out of something that I found to be useful. If I'm going to go to the effort of creating a distribution, I may as well do so for as broad a base as I can. Supporting older Perl versions is sort of like supporting a broad range of OS's. I cannot guess who will be using a module, what OS they'll be using, or what Perl version they will have. If I choose not to support a version or an OS, I am placing a limit on who might be able to use the module. Perhaps that's ok. To the extent that it's practical, I prefer to minimize the requirements placed on the user's Perl environment -- at least the requirements that I'm not able to affect.

One thing I try to do is look at what dependencies I really need, and what requirements they impose as well. If I can't live without Moo, then I'm going to have to give up Perl 5.6, so I may as well code to 5.8+. If I can't reasonably live without a module that requires 5.10, then I may as well code to 5.10+ as well. But what I try not to do is code to 5.10 when all of my dependencies are capable of running under 5.6.

Having said all that, I don't give a second thought to pre-5.6.

One module that I'm involved in currently has dependencies that require 5.8, but I'm in the process of re-working it to use a different dependency so that I can support 5.6 too. (The change in dependencies gets me a few other improvements too, in this case). And this all started with a kind message from someone who has provided useful feedback on some of my other work. In this case the request went something like this: "It would be useful to me if XYZ could support 5.6, and here's what I can do to help in that regard." So there are still those out there who have a need, and some of them are appreciative and willing to extend a helpful hand in recapturing some backward compatibility.