=====================
 Development version
=====================

This document describes in-flight development work.

.. warning::

    Please do not edit this file by hand (doing so will likely cause merge
    conflicts for other Pull Requests). Instead, create a new file in the
    `docs/source/whatsnew/pr` folder


Added a ``Valid`` widget which inherits the ``_Bool`` widget and displays a green checkmark or red cross depending on the truth of ``.value``.

Callbacks registered with the ``Widget.on_some_change`` method are passed the Backbone model ``change`` event's arguments.

The serialization of widget traitlets can be customized.  Custom serialization can use binary message buffers.  Refer to :ghpull:`7757` for more information.

Code raising ``DeprecationWarning``
entered by the user in an interactive session will now display the warning by
default. See :ghpull:`8480` an :ghissue:`8478`.

The `--deep-reload` flag and the corresponding options to inject `dreload` or
`reload` into the interactive namespace have been deprecated, and will be
removed in future versions. You should now explicitly import `reload` from
`IPython.lib.deepreload` to use it.

.. DO NOT EDIT THIS LINE BEFORE RELEASE. FEATURE INSERTION POINT.


Backwards incompatible changes
------------------------------


.. DO NOT EDIT THIS LINE BEFORE RELEASE. INCOMPAT INSERTION POINT.