Update whats new for 4.2.1 release

docs/source/whatsnew/version4.rst

@@ -1,84 +1,92 b''
 ============
  4.x Series
 ============
 
+IPython 4.2.1
+=============
+
+IPython 4.2.1 (July, 2016) includes various bugfixes and improvements over 4.2.0
+
+- Only requires ``backports`` package on Python 2.
+- Bugfix(feature regression): Configuration options on CLI get precedence on configuration options. 
+
 IPython 4.2
 ===========
 
 IPython 4.2 (April, 2016) includes various bugfixes and improvements over 4.1.
 
 - Fix ``ipython -i`` on errors, which was broken in 4.1.
 - The delay meant to highlight deprecated commands that have moved to jupyter has been removed.
 - Improve compatibility with future versions of traitlets and matplotlib.
 - Use stdlib :func:`python:shutil.get_terminal_size` to measure terminal width when displaying tracebacks
   (provided by ``backports.shutil_get_terminal_size`` on Python 2).
 
 You can see the rest `on GitHub <https://github.com/ipython/ipython/issues?q=milestone%3A4.2>`__.
 
 
 IPython 4.1
 ===========
 
 IPython 4.1.2 (March, 2016) fixes installation issues with some versions of setuptools.
 
 Released February, 2016. IPython 4.1 contains mostly bug fixes,
 though there are a few improvements.
 
 
 - IPython debugger (IPdb) now supports the number of context lines for the
   ``where`` (and ``w``) commands. The `context` keyword is also available in
   various APIs. See PR :ghpull:`9097`
 - YouTube video will now show thumbnail when exported to a media that do not
   support video. (:ghpull:`9086`)
 - Add warning when running `ipython <subcommand>` when subcommand is
   deprecated. `jupyter` should now be used.
 - Code in `%pinfo` (also known as `??`) are now highlighter (:ghpull:`8947`)
 - `%aimport` now support module completion. (:ghpull:`8884`)
 - `ipdb` output is now colored ! (:ghpull:`8842`)
 - Add ability to transpose columns for completion: (:ghpull:`8748`)
 
 Many many docs improvements and bug fixes, you can see the
 `list of changes <https://github.com/ipython/ipython/compare/4.0.0...4.1.0>`_
 
 IPython 4.0
 ===========
 
 Released August, 2015
 
 IPython 4.0 is the first major release after the Big Split.
 IPython no longer contains the notebook, qtconsole, etc. which have moved to
 `jupyter <https://jupyter.readthedocs.org>`_.
 IPython subprojects, such as `IPython.parallel <https://ipyparallel.readthedocs.org>`_ and `widgets <https://ipywidgets.readthedocs.org>`_ have moved to their own repos as well.
 
 The following subpackages are deprecated:
 
 - IPython.kernel (now jupyter_client and ipykernel)
 - IPython.consoleapp (now jupyter_client.consoleapp)
 - IPython.nbformat (now nbformat)
 - IPython.nbconvert (now nbconvert)
 - IPython.html (now notebook)
 - IPython.parallel (now ipyparallel)
 - IPython.utils.traitlets (now traitlets)
 - IPython.config (now traitlets.config)
 - IPython.qt (now qtconsole)
 - IPython.terminal.console (now jupyter_console)
 
 and a few other utilities.
 
 Shims for the deprecated subpackages have been added,
 so existing code should continue to work with a warning about the new home.
 
 There are few changes to the code beyond the reorganization and some bugfixes.
 
 IPython highlights:
 
 - Public APIs for discovering IPython paths is moved from :mod:`IPython.utils.path` to :mod:`IPython.paths`.
   The old function locations continue to work with deprecation warnings.
 - 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.