Here is the main way to choose the version of a Domogik package : <major>.<minor>. If needed, you may use alpha and beta notations : 1.0a1, 1.0b3. In all cases, the version number must respect the PEP 386.
The first release of your package should be named 0.1. The following releases should also be named “0.x” until the package is fully functionnal : then you will switch to 1.0 version number. You may want to use some alpha, beta or candidates releases like 1.0a1, 1.0b3, 1.0c1 before using the final 1.0 version number.
After the 1.0 has been published, if you need to make bugfixes or little evolutions, you may use 1.1, 1.2, ... If you want, you can also use alpha, beta and candidates : 1.1c1.
If you have have to make big evolutions in your package, you may switch to the next major version : 2.0.