# Django 2.1.8.dev20190330215650 documentation

# Django 1.8.4 release notes

August 18, 2015

Django 1.8.4 fixes a security issue and several bugs in 1.8.3.

## Denial-of-service possibility in `logout()` view by filling session store

Previously, a session could be created when anonymously accessing the `django.contrib.auth.views.logout()` view (provided it wasn't decorated with `login_required()` as done in the admin). This could allow an attacker to easily create many new session records by sending repeated requests, potentially filling up the session store or causing other users' session records to be evicted.

The `SessionMiddleware` has been modified to no longer create empty session records, including when `SESSION_SAVE_EVERY_REQUEST` is active.

## Bugfixes

- Added the ability to serialize values from the newly added `UUIDField` (#25019).
- Added a system check warning if the old `TEMPLATE_*` settings are defined in addition to the new `TEMPLATES` setting.
- Fixed `QuerySet.raw()` so `InvalidQuery` is not raised when using the `db_column` name of a `ForeignKey` field with `primary_key=True` (#12768).
- Prevented an exception in `TestCase.setUpTestData()` from leaking the transaction (#25176).
- Fixed `has_changed()` method in `contrib.postgres.forms.HStoreField` (#25215, #25233).
- Fixed the recording of squashed migrations when running the `migrate` command (#25231).
- Moved the unsaved model instance assignment data loss check to `Model.save()` to allow easier usage of in-memory models (#25160).
- Prevented `varchar_patterns_ops` and `text_patterns_ops` indexes for `ArrayField` (#25180).