Calendar-versioned software (or “calver”), in contrast to semantically versioned software (or “semver”), is released on regular intervals, rather than on the occurrence of features, bug fixes, or backwards compatibility breaking changes. This method of releasing software, notably used by Twisted and various related projects, eschews the “major.minor.patchlevel” format and the guarantees of a semver regime and instead focuses on providing robust backwards compatibility, clear deprecation cycles, and frequent but smaller releases. This talk discusses some of the trials and tribulations of the release process of such a project, Twisted, and the ways that it makes it work, as well as what tools are available to make the process easier if you wish to implement it yourself.