Important to note that postfix dereferencing is experimental, and does not replace the existing method of dereferencing.
Also, I think the deprecation of core CGI.pm is pretty major. For now it just issues a deprecation warning, but will be removed totally from core in future versions, only being available via the CPAN.
https://metacpan.org/pod/release/RJBS/perl-5.20.0/pod/perlde...