$ ./1.version.pl 
a is 5.026001
b is v5.26.1
version is v5
version is v5.26.1
c is ж
d is Ж
did not match
$ cat 1.version.pl 
#!/usr/bin/perl -w
use 5.011;
use Path::Tiny;
use POSIX qw(strftime);
use if $] ge '5.016', feature => 'fc';
use if $] lt '5.016', 'Unicode::CaseFold' => 'fc';

my $a = $];
say "a is $a";

my $b = $^V;
say "b is $b";

printf "version is v%d\n", $a;  # Perl's version
printf "version is v%vd\n", $b;  # Perl's version

my $c = "ж";
say "c is $c";

my $d = "Ж";
say "d is $d";

if (fc($c) eq fc($d)){
say "expressions matched";

} else {
    say "did not match";
}
__END__ 
$