To check what is the perl version on your system, use:

perl -v

This is perl, v5.8.7 built for i686-linux

If you need to upgrade your perl installation without breaking your CPanel, please follow this method.

wget http://layer1.cpanel.net/perl588installer.tar.gz
tar xfz perl587installer.tar.gz
cd perl587installer
./install

After this is done, run:

/scripts/upcp

You can also run the following to ensure that all the necessary modules were reinstalled:

/usr/local/cpanel/bin/checkperlmodules

Once you have completed the upgrade, you can check again the perl version (perl -v) to ensure that this was properly installed.