Removed versionadded/changed notes for 1.7.

If a file with ``name`` already exists, an underscore plus a random 7 character

alphanumeric string is appended to the filename before the extension.

.. versionchanged:: 1.7

    Previously, an underscore followed by a number (e.g. ``"_1"``, ``"_2"``,

    etc.) was appended to the filename until an available name in the destination

    directory was found. A malicious user could exploit this deterministic

    algorithm to create a denial-of-service attack. This change was also made

    in Django 1.6.6, 1.5.9, and 1.4.14.

.. versionchanged:: 1.8

    The ``max_length`` argument was added.

Custom Lookups

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

.. versionadded:: 1.7

.. currentmodule:: django.db.models

Django offers a wide variety of :ref:`built-in lookups <field-lookups>` for

.. method:: BaseCommand.check(app_configs=None, tags=None, display_num_errors=False)

    .. versionadded:: 1.7

    Uses the system check framework to inspect the entire Django project for

    potential problems. Serious problems are raised as a :class:`CommandError`;

    warnings are output to stderr; minor notifications are output to stdout.

Field deconstruction

--------------------

.. versionadded:: 1.7

    ``deconstruct()`` is part of the migrations framework in Django 1.7 and

    above. If you have custom fields from previous versions they will

    need this method added before you can use them with migrations.

The counterpoint to writing your ``__init__()`` method is writing the

``deconstruct()`` method. This method tells Django how to take an instance

of your new field and reduce it to a serialized form - in particular, what

``endswith``, ``iendswith``, ``range``, ``year``, ``month``, ``day``,

``isnull``, ``search``, ``regex``, and ``iregex``.

.. versionadded:: 1.7

    If you are using :doc:`Custom lookups </howto/custom-lookups>` the

    ``lookup_type`` can be any ``lookup_name`` used by the project's custom

    lookups.

If you are using :doc:`custom lookups </howto/custom-lookups>`, the

``lookup_type`` can be any ``lookup_name`` used by the project's custom lookups.

Your method must be prepared to handle all of these ``lookup_type`` values and

should raise either a ``ValueError`` if the ``value`` is of the wrong sort (a

development time with ``DEBUG = True``, i.e. without having to collect them

using :djadmin:`collectstatic` first.

.. versionadded:: 1.7

    :class:`django.contrib.staticfiles.testing.StaticLiveServerTestCase` is new

    in Django 1.7. Previously its functionality was provided by

    :class:`django.test.LiveServerTestCase`.

Deployment

==========