I'd be interested in reading where 5.12 is no longer granted access to ActiveStates PPM. Have you considered not using ActiveState and opting for one of the alternatives such as Strawberry Perl?

You can add:

use 5.012;
[download]

to your code to only enable perl 5.12 features even though your running a later version of perl. See use VERSION. That said obviously you want to run your test suite/test procedures to ensure that there are no issues. Backward compatibility and depreciation may be of interest.

Update: fixed typo.