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* Dropped support for Django 1.11, 2.0, and 2.1.
* Added the ``delete_stale_comments`` management command.
* Added db_index to ``object_pk`` and ``is_removed`` fields.
* Altered ``object_pk`` from ``TextField`` to ``CharField(max_length=64)``
so that the field can be indexed on MySQL, too. **Warning:** if you attach
comments to objects whose primary key is serialized to more than 64
characters, you should provide a custom Comment model
(more about that in the documentation) with an appropriate
``object_pk`` field.
* Confirmed support for Python 3.9.
* Added support for Django 3.2.