What's new in 2.2.1 (February XX, 2024)

These are the changes in pandas 2.2.1. See :ref:`release` for a full changelog including other versions of pandas.

Fixed regressions

Fixed performance regression in :meth:`Series.combine_first` (:issue:`55845`)
Fixed regression in :func:`merge_ordered` raising TypeError for fill_method="ffill" and how="left" (:issue:`57010`)
Fixed regression in :meth:`Series.pct_change` raising a ValueError for an empty :class:`Series` (:issue:`57056`)