I tried it, but there are other worries, warnings "Wide character in print at" and @ARGV is still not treated as UTF-8 chars, uc() does not recognize them as chars

And perldoc utf8 says

In case you are wondering: yes, "use encoding ’utf8’;" works much the same as "use utf8;".

In perl58delta i read also:

New Unicode Semantics (no more use utf8, almost)

Previously in Perl 5.6 to use Unicode one would say "use utf8" and then the operations (like string concatenation) were Unicode-aware in that lexical scope.

So i could not even use "use utf8", theoretically ;)