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.
You install one of the many modules from CPAN, i.e. Plack, Dancer, Mojolicious, CGI. The only change is that an old module that has way too much badly implemented functionality has been set on the path towards removal from the default Perl installation.
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...