Perl 5.8.x is no longer supported by the Perl community or p5p. The policy discussed in perlpolicy states that the Perl5 Porters support the two most recent stable releases. Right now that means Perl 5.18 and Perl 5.16. Critical security patches will, to the best of the porters ability, go back three years, which means that even though 5.14 is no longer supported for other critical issues, for critical security issues it may still receive updates if it falls within p5p's ability.

Modules on CPAN often attempt to maintain compatibility with older versions of Perl as well. But this is done on a module-by-module basis at the whim of the module's developer. It's not uncommon to see modules that officially support Perl 5.8, 5.6, or in some cases even earlier Perl releases, though that's becoming harder and harder to do as time marches on, bringing with it increased demand for full Unicode support or other "modern" tools that early Perl5's weren't designed to work with.

Some vendors will ship Linux (or other OS) distributions with older versions of Perl, such as Perl 5.8. In those cases, the vendors may support those older Perl versions even if the Perl community has moved on.

I haven't looked into the wikipedia article's sources. One reason that Perl 5.8 may still be the most popular Perl is that it was around so long before 5.10 came along, and then in the years since 5.10 there have been so many other releases. The point being that no single release from 5.10 onward has had time to become entrenched to the degree that 5.8 did. 5.8 was with us for a long time; there was some stagnation during that era. And as I mentioned earlier, some vendors are still shipping it.