Perl 5.22 deprecated defined arrays. Got a cgi-bin that's not working as a result. How do I downgrade perl to 5.20 system wide?
Checking defined on arrays in Perl is not deprecated but forbidden. It was deprecated since Perl 5.6.1 (releases 2001) and triggered a warning since 5.16 (2012). It now triggers a fatal error instead.
Downgrading the system Perl is a bad idea since there are system tools which depend on it and thus might result in an error if downgraded. But you could install multiple versions of Perl in parallel and then refer to the one you want to use inside your affected cgi-bin scripts. You can use perlbrew for this.