I have 3 x 5.6, 1 x 5.6.1, 3 x 5.8.0, 2 x 5.8.3, 1 x 5.8.6, 2 x 5.10, 1 x 5.12, 4 x 5.14, and 2 x 5.14.2 in my CPAN releases where I like to keep it as low/old as possible.

For all scripts that should work on AIX, HP-UX, Solaris and other non-mainstream *nix OS's, I require 5.14.2.

For anything that requires a fun factor, I won't go below 5.12: I want both $c //= 42; and my $x = $y =~ s{foo\Kbar}{dwok}r;