Your confusion lies in thinking, as you&#x27;ve said, &quot;just a new version of a language.&quot; It&#x27;s actually been a long, 15-year journey that resulted in a completely brand new language. The name is still &#x27;Perl 6&#x27; for historical reasons, but it may as well be called &#x27;Rakudo&#x27;; something people&#x27;ve not heard of yet. The Perl 5 language is still being developed and improved, with a major release every year. Hence, the filename distinction.<p>However, it&#x27;s just a convention. You can have any extension you like (at least on *nix).<p>And to answer your question, no &quot;use v6&quot; is not mandatory. It&#x27;s there so if you run your script with a perl (and not perl6) interpreter, you won&#x27;t get confusing errors.