What's new in 1.4.2 (March ??, 2022)

These are the changes in pandas 1.4.2. See :ref:`release` for a full changelog including other versions of pandas.

Fixed regressions

Fixed regression in :meth:`DataFrame.drop` and :meth:`Series.drop` when :class:`Index` had extension dtype and duplicates (:issue:`45860`)
Fixed memory performance regression in :meth:`Series.fillna` when called on a :class:`DataFrame` column with inplace=True (:issue:`46149`)
Provided an alternative solution for passing custom Excel formats in :meth:`.Styler.to_excel`, which was a regression based on stricter CSS validation. Examples available in the documentation for :meth:`.Styler.format` (:issue:`46152`)
Fixed regression in :meth:`DataFrame.loc.__setitem__` losing :class:`MultiIndex` names if :class:`DataFrame` was empty before (:issue:`46317`)

Fix some cases for subclasses that define their _constructor properties as general callables (:issue:`46018`)
Fixed "longtable" formatting in :meth:`.Styler.to_latex` when column_format is given in extended format (:issue:`46037`)

.. contributors:: v1.4.1..v1.4.2|HEAD