I doubt it's complicated to transform ...

Not at all in one line of a 20-line script. But to do it reliably across many files in a 1,000,000 line codebase without breaking anything? That's a different matter entirely. Never mind the shops who are running 15-year-old Perl systems with no Perl maintainer on the books.

a similar discussion like use v7; was.

Quite so. I applaud the enthusiasm of those who proposed it but to do so in a language which has always striven for backwards compatibility was inevitably going to be a big task. For every agile developer crying, "Throw it all out!" there is a sysadm or project manager with a legacy burden screaming "Keep it all in!".

I think it's more complicated and the real problem is communication.

Anyway pragmas are the solution for most of this, and we already did this with strict which changed the language considerably.

Create something like a symlink perl7 pointing to perl and whenever the executable is run under the new name it'll activate use v7; automatically.

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}