Pillow/docs/releasenotes/versioning.rst

.. _versioning:

Versioning
==========

Pillow follows `Semantic Versioning <https://semver.org/>`_:

    Given a version number MAJOR.MINOR.PATCH, increment the:

    1. MAJOR version when you make incompatible API changes,
    2. MINOR version when you add functionality in a backwards compatible manner, and
    3. PATCH version when you make backwards compatible bug fixes.

Quarterly releases ("`Main Release <https://github.com/python-pillow/Pillow/blob/main/RELEASING.md#user-content-main-release>`_")
bump at least the MINOR version, as new functionality has likely been added in the
prior three months.

A quarterly release bumps the MAJOR version when incompatible API changes are
made, such as removing deprecated APIs or dropping an EOL Python version. In practice,
these occur every 12-18 months, guided by
`Python's EOL schedule <https://devguide.python.org/#status-of-python-branches>`_, and
any APIs that have been deprecated for at least a year are removed at the same time.

PATCH versions ("`Point Release <https://github.com/python-pillow/Pillow/blob/main/RELEASING.md#user-content-point-release>`_"
or "`Embargoed Release <https://github.com/python-pillow/Pillow/blob/main/RELEASING.md#user-content-embargoed-release>`_")
are for security, installation or critical bug fixes. These are less common as it is
preferred to stick to quarterly releases.

Between quarterly releases, ``.dev0`` is appended to the ``main`` branch, indicating that
this is not a formally released copy.