From early on, Diamond was run as a master is stable release style. The belief was that master should always be stable and ready to deploy to production. This lead to the odd release system we currently have.
The current version is generated by the bash script at https://github.com/python-diamond/Diamond/blob/master/version.sh
The major and minor version numbers are generated based on the latest annotated tag.
Cutting a new major/minor version is done via: