Semantic versioning of force fields follows MAJOR(x).MINOR(y).PATCH scheme and new versions will be released as OpenFF x.y.z:

x : functional form change and/or major scientific update

y : parameter refit epoch

z : bugfix / hotfix

Generally, major increments MAY indicate a functional form or compatibility change, but don't NEED to. However, if compatibility DOES change, then major version number MUST increment.

Codenames:

Force field versions with major updates will be referred to as generations , not releases, for clearer communication purposes. Each new force field generation will have a specific codename associated with it, while the minor and patch releases will be captured in openff-x.y.z version names. The codenames will be given after herbs.

Biomolecular force fields:

amber14sb will be ported to amber14SB.offxml. After the first refit, biomolecular force field parameters will become a part of openff-x.y.z with documentation describing the details.