Comment by Mithaldu

For those who do not wish to read the entire changelog, the two important changes are these:

    Subroutine Signatures

    sub foo ($left, $right) {
        return $left + $right;
    }

https://metacpan.org/pod/release/RJBS/perl-5.20.0/pod/perlsu...

    Postfix dereferencing

    $array_ref->@*;

instead of

    @{$array_ref};

https://metacpan.org/pod/release/RJBS/perl-5.20.0/pod/perlde...