G'day FryingFinn,

Modifying the system Perl is a bad idea. Changes you make may affect how the OS operates. Updates to the OS may affect how your programs work.

There are various options available for Mac OSX. I've been using Perlbrew for some years without any problems. Not only does this avoid interference with the system Perl, it also allows you to install more recent versions (5.18.2 is the current stable version).

I recommend you install a version of Perl for your own use before following the advice to update modules.