While I am really happy that perl moves forward, things get fixed or deprecated and later removed but I know several companies that are still using 5.6.x and even older versions of perl. The gap is widening for many companies and I am not sure what to think about it.
Recently I asked on the mailing list of Israel.pm: Why are you (or your company) still using an older version of Perl? and I got a couple of good answers. Then, today I saw a post on the perl5porters list by H.Merijn Brand that was related to this.
Let's look at these companies.
The systems as they are now are working, none of the features in newer versions of perl seem to be very important to those companies. (Actually I think even that might not be true, just companies learned to live with some of the shortcomings of old versions of perl)
Upgrading perl only seems to involve cost: Someone might need to fix the code if it was using deprecated or changed features. Someone needs to verify that everything works well and if the code was written 5-10 years ago then the number of automated tests will be very low. Someone will have to install the newer perl on every machine and upgrade the applications.
There is also a risk - no matter how much you verified the code - that something will stop working which can cause downtime, lost revenue or penalties.
So there does not seem to be a compelling reason to make that investment.
On the other hand...
It will be cheaper to develop for newer versions of perl
More and more modules on CPAN require 5.8.x and even 5.10.x. In some cases you can find an old version of the module that can work on older perl but it is getting more and more difficult. In addition there are new modules that from the beginning required a relatively recent version of perl. (e.g. both Devel::NYTProf and Moose require 5.8.1)
That means the company won't be able to leverage the extra work that went into the CPAN modules so it won't be able to enjoy the saving opportunities in development cost. In short, developing on newer versions of perl would cost less money than developing on older versions of perl.
The same is true with core perl. The new features (e.g. say, given, named capture, smart-match) help reducing development cost for future code.
Staying with older perl will cost extra money in future development.
Easier to find good developers for modern Perl
There is another reason I can think of. Companies complain that it is hard to find good perl developers. I am quite sure that it is much harder to convince a good perl developer to work in a shop that sticks with an old version of perl than in a shop that uses modern perl. So staying with old perl will cost in recruiting and retaining Perl developers. We can go back in time and ask again: Is it really hard to find good Perl programmers?
It costs more to get any support for older versions of Perl and older CPAN modules
Older versions of perl are not supported. Just as with any other technology if you stay with an old version you are on your own. You won't find open source developers to help you free of charge and even finding commercial support will be increasingly hard and thus increasingly expensive. So there is a risk factor in staying with old versions of perl.
Are there other reasons to upgrade perl?
Published on 2009-10-30 by Gabor Szabo