Check the list of modules installed on your system with

perl -MCPAN -eautobundle
[download]

You can always use x.y_z if you want to emulate x.y.z. The underscore will be ignored, being treated as a visual separator for digits, and your number will be treated as x.yz.

At the moment the x.y.z notation is interpreted differently if different versions of Perl. For example, it's a v-string in Perl 5.6.1 and it's translated into a 3 characters string (not necessarily threee bytes), the first character having code x, the second having code y, the third having code z. So, if you try

perl -e'print 33.34.35'
[download]

My conclusion is that, for the time being, x.yz or x.y_z are more backwards compatible than x.y.z or vx.y.z.

As newer versions of Perl replace the old ones, v-strings will probably be the preferred way. You can always require 5.6 in your code and start using them right now without ambiguity.

The other question, about version numbering schemes, is more about personal taste. Some developers use even minor releases for stable versions, odd for development (no pun intended).

So, for example, Linux kernel 2.4 series are (supposed to be) stable versions, being 4 an even number, while series 2.3 used to be the development branch that lead to 2.4.

Another issue is the starting number, some developers like to start from 0.x versions (meaning it can be still experimental), while other feel more confident and their versions start with 1.x.

Finally, some developers like versions such as 1.03, others prefer 1.3. A minor change would be 1.04 in the first case (or maybe even 1.03_1 or 1.03_01 or...) and 1.31 in the second. It doesn't matter which one you chose, I think. The important thing, in my opinion, is preserving a correct numerical progression.

Happy releasing!

-- TMTOWTDI