It will coexist out of the box.
Remember this is Linux!

Version 5.6.1 will be the default after the installation.
I.e. /usr/bin/perl will be a link to version 5.6.1.

There should also be a /usr/bin/perl5.005.

You will have to patch the shebang in your scripts accordingly.

The only problem I experienced was with perldoc, but with shifting a link everything was fine.