[1.10.x] Fixed #26713 -- Documented resolving deprecation warnings before upgrade.

dependencies may not yet support the new Django version. In these cases you may

have to wait until new versions of your dependencies are released.

Resolving deprecation warnings

==============================

Before upgrading, it's a good idea to resolve any deprecation warnings raised

by your project while using your current version of Django. Fixing these

warnings before upgrading ensures that you're informed about areas of the code

that need altering.

In Python, deprecation warnings are silenced by default. You must turn them on

using the ``-Wall`` Python command line option or the :envvar:`PYTHONWARNINGS`

environment variable. For example, to show warnings while running tests:

.. code-block:: console

    $ python -Wall manage.py test

If you're not using the Django test runner, you may need to also ensure that

any console output is not captured which would hide deprecation warnings. For

example, if you use `py.test`:

.. code-block:: console

    $ PYTHONWARNINGS=all py.test tests --capture=no

Resolve any deprecation warnings with your current version of Django before

continuing the upgrade process.

Third party applications might use deprecated APIs in order to support multiple

versions of Django, so deprecation warnings in packages you've installed don't

necessarily indicate a problem. If a package doesn't support the latest version

of Django, consider raising an issue or sending a pull request for it.

Installation

============

=======

When the new environment is set up, :doc:`run the full test suite

</topics/testing/overview>` for your application. In Python 2.7+, deprecation

warnings are silenced by default. It is useful to turn the warnings on so they

are shown in the test output (you can also use the flag if you test your app

manually using ``manage.py runserver``):

</topics/testing/overview>` for your application. Again, it's useful to turn

on deprecation warnings on so they're shown in the test output (you can also

use the flag if you test your app manually using ``manage.py runserver``):

.. code-block:: console