Before merging your contribution to an openfisca package, you are required to increment the version of this package.
The semantic versionning convention, applied here, requires you to:
Given a version number MAJOR.MINOR.PATCH, increment the:
MAJOR version when you make incompatible API changes,
MINOR version when you add functionality in a backwards-compatible manner, and
PATCH version when you make backwards-compatible bug fixes.
It is thus crucial to determine whether your changes are backwards-compatible. If, during a hackathon, a contributor has written a reform to Openfisca, would this reform still work after adding your changes ?