I think you can learn most/all of Perl 5.32 with http://modernperlbooks.com/books/modern_perl_2016/ , and it appears this is, initially, going to be 5.32 with some saner defaults. So you could really start now, given that.
> This beloved guide is now completely updated for Perl 5.22.
I've been working with Perl since about 5.20 and am on 5.31 or 5.32 and haven't noticed many breaking changes FWIW.
The 2016 edition covers most of what's in 5.32; if I were to do an update for Perl 5.32, I'd include postfix dereferencing and the built-in function signature mechanisms now that they're very stable and supported.
> This beloved guide is now completely updated for Perl 5.22.
I've been working with Perl since about 5.20 and am on 5.31 or 5.32 and haven't noticed many breaking changes FWIW.