Marshmallow

********************

Features:

- *Backwards-incompatible*: ``missing`` and ``default`` values are
passed in deserialized form (:issue:`378`). Thanks :user:`chadrik` for
the suggestion and thanks :user:`lafrech` for the PR.

Bug fixes:

- Includes the bugfix from 2.15.1.

********************

Features:

- *Backwards-incompatible*: Add ``data_key`` parameter to fields for
specifying the key in the input and output data dict. This
parameter replaces both ``load_from`` and ``dump_to`` (:issue:`717`).
Thanks :user:`lafrech`.
- *Backwards-incompatible*: When ``pass_original=True`` is passed to one
of the decorators and a collection is being (de)serialized, the
``original_data`` argument will be a single object unless
``pass_many=True`` is also passed to the decorator (:issue:`315`,
:issue:`743`). Thanks :user:`stj` for the PR.
- *Backwards-incompatible*: Don't recursively check nested required
fields when the ``Nested`` field's key is missing (:issue:`319`). This
reverts :pr:`235`. Thanks :user:`chekunkov` reporting and thanks
:user:`lafrech` for the PR.
- *Backwards-incompatible*: Change error message collection for ``Dict`` field (:issue:`730`). Note:
this is backwards-incompatible with previous 3.0.0bX versions.
Thanks :user:`shabble` for the report and thanks :user:`lafrech` for the PR.

********************

Features:

- *Backwards-incompatible*: Schemas are always strict (:issue:`377`).
The ``strict`` parameter is removed.
- *Backwards-incompatible*: ``Schema().load`` and ``Schema().dump`` return ``data`` instead of a
``(data, errors)`` tuple (:issue:`598`).
- *Backwards-incompatible*: ``Schema().load(None)`` raises a
``ValidationError`` (:issue:`511`).

See :ref:`upgrading_3_0` for a guide on updating your code.

Thanks :user:`lafrech` for implementing these changes.
Special thanks to :user:`MichalKononenko`, :user:`douglas-treadwell`, and
:user:`maximkulkin` for the discussions on these changes.


Other changes:

- *Backwards-incompatible*: Field name is not checked when ``load_from``
is specified (:pr:`714`). Thanks :user:`lafrech`.

Support:

- Add `Code of Conduct <https://marshmallow.readthedocs.io/en/dev/code_of_conduct.html>`_.

********************

Bug fixes:

- Fixes ``ValidationError.valid_data`` when a nested field contains errors
(:issue:`710`). This bug was introduced in 3.0.0b3. Thanks
:user:`lafrech`.

Other changes:

- *Backwards-incompatible*: ``Email`` and ``URL`` fields don't validate
on serialization (:issue:`608`). This makes them more consistent with the other
fields and improves serialization performance. Thanks again :user:`lafrech`.
- ``validate.URL`` requires square brackets around IPv6 URLs (:issue:`707`). Thanks :user:`harlov`.

********************

Features:

- Add support for structured dictionaries by providing values and keys arguments to the
``Dict`` field's constructor. This mirrors the ``List``
field's ability to validate its items (:issue:`483`). Thanks :user:`deckar01`.

Other changes:

- *Backwards-incompatible*: ``utils.from_iso`` is deprecated in favor of
``utils.from_iso_datetime`` (:issue:`694`). Thanks :user:`sklarsa`.

********************

Features:

- Add support for millisecond, minute, hour, and week precisions to
``fields.TimeDelta`` (:issue:`537`). Thanks :user:`Fedalto` for the
suggestion and the PR.
- Includes features from release 2.14.0.


Support:

- Copyright year in docs uses ``CHANGELOG.rst``'s modified date for
reproducible builds (:issue:`679`). Thanks :user:`bmwiedemann`.
- Test against Python 3.6 in tox. Thanks :user:`Fedalto`.
- Fix typo in exception message (:issue:`659`). Thanks :user:`wonderbeyond`
for reporting and thanks :user:`yoichi` for the PR.