Python packaging.version.parse became more restrictive at parsing strings. Therefore introduce the new variables ON_VER and OFF_VER, which has the same meaning like ON and OFF but can be parsed to versions.
Be careful, if you use the Variables ON and OFF in your project beside comparison.
Change name of develop version to 1.0.0-dev in the example, that it can be parsed to a version.
developversion to1.0.0-devin the example, that it can be parsed to a version.