I agree that you should not upgrade perl just for the upgrade, and - also - not because some wise monk tells you to without a reasonable reason. I do agree with the volunteer-time that chromatic mentions, but not with that being a reason to upgrade. He has been around long enough to know some problems do not have any issues in perl versions (other than maybe the updated documentation coming with it).

Nor are there any valid reasons to force anyone to move along to the *latest* version of perl. There may be very good reasons to upgrade, even with the problem at hand, but that does not imply a forced move from 5.6.1 to 5.18.1 where 5.12.3 might be more convenient.

Note however that perl releases are not made just for the release numbers. However the people in charge (the CEO's, not the perl5 developers) like to see the language alive and being actually developed, those updates have a reason: for most the updates are not because of the new features, but because of bug fixes. A lot of complaints that we as monks see pass by here do get fixed.

The example given by boftx is imho the worst example to have to opinion not to upgrade. I love defined-or to the extend that I have the feature available for *every* version of perl5.8.x. I can't live without it in my daily work. All production scripts use it. Though by now our production machines and all customers use 5.14.2 as a minimum perl. Also not that this seldom is one of the reasons mentioned in answers here where the OP is asked to upgrade perl, as this was a new feature in 5.10, not a bugfix.

A next thing I want to mention is related to what chromatic mentions in volunteer time use: the minimum version of perl for the toolchain support has been raised to perl-5.8.1 with an option to be raised to 5.8.4 is 5.8.1 proves to be too restrictive. This was done in the Lancaster Consensus. The reason is that it just takes too much time of the authors of the toolchain to be 5.6 compliant. Having a minimum version as guarantee can make code a lot more simple to write and to maintain. The toolchain however is used for EVERY module on CPAN. This causes the call to upgrade your perl to the minimal version of perl supported by the toolchain, as though your reported bug might not be a perl-bug or a CORE-bug, the bug might have been fixed in a newer release of the CPAN module, but you cannot install it, as the toolchain used to build and install the module does not work on your old version of perl.