This is a sort-of response to mst's On Perl 5.6 post. Mostly, I agree with Matt about not gratuitously breaking 5.6 compatibility (i.e. to "force people to upgrade").
However, in recent years, I've never received a single bug report or patch from a person actually using 5.6 for anything except smoke testing things on 5.6.
The argument seems to be: "because I think it's important to test things on 5.6, you should make it possible for me to do so". This seems circular.
Testing on 5.6 is pointless if no one is using 5.6 for anything except testing 5.6.
There is an argument sometimes made that if there are users on 5.6, then they should just upgrade. That seems rather obviously wrong, since if there really are such people, there are probably good reasons why they can't. But at the same time, it seems entirely inconsistent for someone to insist that they can't possibly upgrade their perl to something released in the last decade, yet they want the latest and greatest from CPAN.
If there really are people using 5.6 for real, do they really expect CPAN modules to just work? Are they really put out if they don't? Or have they learned to work around it, just like they've worked around the myriad of feature gaps and bug fixes in the last dozen years?
As far as accepting patches for 5.6 support goes, I have very mixed feelings about it. Reviewing patches takes time. Patches accepted might then implicitly indicate support for 5.6 going forward. And if there are bugs, the original patch author might not be around.
So a simple patch that restores 5.6 compatibility might be fine. E.g. "hey, I removed your 'use 5.008' and tested it on 5.6.2 and it passed tests just fine!". But a complex, possibly fragile workaround burdens the receiver if accepted.
If a real person actually using 5.6 asked me to do that, I might accept, depending on how ugly the patch is. But I'm far, far less inclined to do so when sent a gnarly patch by some self-appointed compatibility police telling me 5.6 support is still important "just because".
While it's not for me to tell people what to do with their volunteer time, I suspect that whatever time people are spending writing 5.6 patches and doing 5.6 smoke testing could be far more valuably spent on other things that affect orders of magnitude more real users.