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# Django REST framework 3.11

The 3.11 release adds support for Django 3.0.

* Our supported Python versions are now: 3.5, 3.6, 3.7, and 3.8.
* Our supported Django versions are now: 1.11, 2.0, 2.1, 2.2, and 3.0.

This release will be the last to support Python 3.5 or Django 1.11.

## OpenAPI Schema Generation Improvements

The OpenAPI schema generation continues to mature. Some highlights in 3.11
include:

* Automatic mapping of Django REST Framework renderers and parsers into OpenAPI
  request and response media-types.
* Improved mapping JSON schema mapping types, for example in HStoreFields, and
  with large integer values.
* Porting of the old CoreAPI parsing of docstrings to form OpenAPI operation
  descriptions.

In this example view operation descriptions for the `get` and `post` methods will
be extracted from the class docstring:

```python
class DocStringExampleListView(APIView):
    """
    get: A description of my GET operation.
    post: A description of my POST operation.
    """

    permission_classes = [permissions.IsAuthenticatedOrReadOnly]

    def get(self, request, *args, **kwargs): ...

    def post(self, request, *args, **kwargs): ...
```

## Validator / Default Context

In some circumstances a Validator class or a Default class may need to access the serializer field with which it is called, or the `.context` with which the serializer was instantiated. In particular:

* Uniqueness validators need to be able to determine the name of the field to which they are applied, in order to run an appropriate database query.
* The `CurrentUserDefault` needs to be able to determine the context with which the serializer was instantiated, in order to return the current user instance.

Our previous approach to this was that implementations could include a `set_context` method, which would be called prior to validation. However this approach had issues with potential race conditions. We have now move this approach into a pending deprecation state. It will continue to function, but will be escalated to a deprecated state in 3.12, and removed entirely in 3.13.

Instead, validators or defaults which require the serializer context, should include a `requires_context = True` attribute on the class.

The `__call__` method should then include an additional `serializer_field` argument.

Validator implementations will look like this:

```python
class CustomValidator:
    requires_context = True

    def __call__(self, value, serializer_field): ...
```

Default implementations will look like this:

```python
class CustomDefault:
    requires_context = True

    def __call__(self, serializer_field): ...
```

---

## Funding

REST framework is a *collaboratively funded project*. If you use
REST framework commercially we strongly encourage you to invest in its
continued development by **[signing up for a paid plan][funding]**.

*Every single sign-up helps us make REST framework long-term financially sustainable.*

<ul class="premium-promo promo">
    <li><a href="https://getsentry.com/welcome/" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/sentry130.png)">Sentry</a></li>
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    <li><a href="https://software.esg-usa.com" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/esg-new-logo.png)">ESG</a></li>
    <li><a href="https://rollbar.com" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/rollbar2.png)">Rollbar</a></li>
    <li><a href="https://cadre.com" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/cadre.png)">Cadre</a></li>
    <li><a href="https://hubs.ly/H0f30Lf0" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/kloudless-plus-text.png)">Kloudless</a></li>
    <li><a href="https://lightsonsoftware.com" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/lightson-dark.png)">Lights On Software</a></li>
    <li><a href="https://retool.com/?utm_source=djangorest&utm_medium=sponsorship" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/retool-sidebar.png)">Retool</a></li>
</ul>
<div style="clear: both; padding-bottom: 20px;"></div>

*Many thanks to all our [wonderful sponsors][sponsors], and in particular to our premium backers, [Sentry](https://getsentry.com/welcome/), [Stream](https://getstream.io/?utm_source=drf&utm_medium=banner&utm_campaign=drf), [ESG](https://software.esg-usa.com/), [Rollbar](https://rollbar.com/?utm_source=django&utm_medium=sponsorship&utm_campaign=freetrial), [Cadre](https://cadre.com), [Kloudless](https://hubs.ly/H0f30Lf0), [Lights On Software](https://lightsonsoftware.com), and [Retool](https://retool.com/?utm_source=djangorest&utm_medium=sponsorship).*

[sponsors]: https://fund.django-rest-framework.org/topics/funding/#our-sponsors
[funding]: funding.md
