Show new format, note on has_index_names

Author: chris-b1

doc/source/whatsnew/v0.17.0.txt

@@ -189,8 +189,8 @@ See the :ref:`docs <io.sas>` for more details.
 
 Changes to Excel with ``MultiIndex``
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-In version 0.16.2 a ``DataFrame`` with ``MultiIndex`` columns could not be written to Excel via `to_excel`.
-That functionality has been added (:issue:`10564`), along with updating  `read_excel` so that the data can
+In version 0.16.2 a ``DataFrame`` with ``MultiIndex`` columns could not be written to Excel via ``to_excel``.
+That functionality has been added (:issue:`10564`), along with updating  ``read_excel`` so that the data can
 be read back with no loss of information by specifying which columns/rows make up the ``MultiIndex``
 in the `header` and `index_col` parameters (:issue:`4679`)
 
@@ -214,6 +214,23 @@ in the `header` and `index_col` parameters (:issue:`4679`)
    import os
    os.remove('test.xlsx')
 
+Previously, it was necessary to specifying the ``has_index_names`` argument in ``read_excel``
+if the serialized data had index names.  For version 0.17 the ouptput format of ``to_excel``
+has been changed to make this keyword unnecessary - the change is shown below.
+
+**Old**
+
+.. image:: _static/old-excel-index.png
+
+**New**
+
+.. image:: _static/new-excel-index.png
+
+.. warning::
+
+    Excel files saved in version 0.16.2 or prior that had index names will still able to be read in,
+    but the ``has_index_names`` argument must specified to ``True``.
+
 See the :ref:`documentation <io.excel>` for more details.
 
 .. _whatsnew_0170.enhancements.other: