I am forced to use perl version 5.6
Does this mean that you're not allowed to install a newer version of Perl? Or do you have keep your code compatible with Perl 5.6?
If your system has access to the internet or a USB port, I can think of one possible route around the Perl 5.6 limitation.
Check out Strawberry Perl, which has a portable version available. If your system has internet access, you can download that directly to your system and can install any needed/desired modules directly from CPAN. If your system does not have access to the internet and has a USB port, you can use another system with internet access and put the portable Strawberry Perl on a USB stick drive. And use that system to add any needed/desired modules to that same USB stick drive.
With portable Strawberry Perl, there is no installation. Just download the zip file and extract it. To use it, you have to run a batch file they provide. That batch file basically opens a command prompt and sets the environment variables for just that command prompt. Just run that batch file and use the command prompt that it opens.
If you need/want to share your code with others, you can install PAR::Packer and use its pp utility to bundle your code into a stand-alone executable. Whoever uses that executable does not even need Perl to be installed to use it.
Just tossing out a suggestion for a possible work around.