I think you should move away from custom scripts for configuration management and consider the excellent choice of ready made tools: CFEngine, Puppet, Chef, and Ansible to name a few.

I do much consulting on CFEngine, feel free to drop me a line if you have questions.

I do sometimes have to maintain Perl programs that work with multiple versions. Usually, you have to make the program work on the system that has the oldest Perl installed, the later versions of Perl will usually accept this code without complaint, but you can't be too careful. TEST, TEST, TEST.