But right now, especially once Perl development really picked up, it might be time to "divorce" the two languages. It seems more like Algol60 vs. Algol68, or Modula-2 vs. Modula-3. Sure, there's a number in there, but it isn't just about the version of the main implementation.
Having said that, kudos to the Perl team. I really like that they now release new versions pretty regularly, which is a good sign to show people that Perl5 ist still very much alive and nobody needs to hold their breath for the time being.
If only I could use something more recent than 5.8 at work...