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# What’s new in 1.4.1 (February 12, 2022)

These are the changes in pandas 1.4.1. See Release notes for a full changelog including other versions of pandas.

## Fixed regressions

- Regression in `Series.mask()` with `inplace=True` and `PeriodDtype` and an incompatible `other` coercing to a common dtype instead of raising (GH 45546)

- Regression in `assert_frame_equal()` not respecting `check_flags=False` (GH 45554)

- Regression in `DataFrame.loc()` raising `ValueError` when indexing (getting values) on a `MultiIndex` with one level (GH 45779)

- Regression in `Series.fillna()` with `downcast=False` incorrectly downcasting `object` dtype (GH 45603)

- Regression in `api.types.is_bool_dtype()` raising an `AttributeError` when evaluating a categorical `Series` (GH 45615)

- Regression in `DataFrame.iat()` setting values leading to not propagating correctly in subsequent lookups (GH 45684)

- Regression when setting values with `DataFrame.loc()` losing `Index` name if `DataFrame` was empty before (GH 45621)

- Regression in `join()` with overlapping `IntervalIndex` raising an `InvalidIndexError` (GH 45661)

- Regression when setting values with `Series.loc()` raising with all `False` indexer and `Series` on the right hand side (GH 45778)

- Regression in `read_sql()` with a DBAPI2 connection that is not an instance of `sqlite3.Connection` incorrectly requiring SQLAlchemy be installed (GH 45660)

- Regression in `DateOffset` when constructing with an integer argument with no keywords (e.g. `pd.DateOffset(n)`) would behave like `datetime.timedelta(days=0)` (GH 45643, GH 45890)

## Bug fixes

- Fixed segfault in `DataFrame.to_json()` when dumping tz-aware datetimes in Python 3.10 (GH 42130)

- Stopped emitting unnecessary `FutureWarning` in `DataFrame.sort_values()` with sparse columns (GH 45618)

- Fixed window aggregations in `DataFrame.rolling()` and `Series.rolling()` to skip over unused elements (GH 45647)

- Fixed builtin highlighters in `Styler` to be responsive to `NA` with nullable dtypes (GH 45804)

- Bug in `apply()` with `axis=1` raising an erroneous `ValueError` (GH 45912)

## Other

- Reverted performance speedup of `DataFrame.corr()` for `method=pearson` to fix precision regression (GH 45640, GH 42761)

## Contributors

For contributors, please see /usr/share/doc/contributors_list.txt or https://github.com/pandas-dev/pandas/graphs/contributors