There were multiple discussions about versioning around the Phab and Gerrit, some of them:
- T106121: RFC removing old code / code cleanup
- https://gerrit.wikimedia.org/r/#/c/pywikibot/core/+/411613/
- https://gerrit.wikimedia.org/r/#/c/pywikibot/core/+/409823/
Let's move the discussion to one task. Current state (6/2018):