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# What’s new in 1.3.1 (July 25, 2021)

These are the changes in pandas 1.3.1. See Release notes for a full changelog including other versions of pandas.

## Fixed regressions

- Pandas could not be built on PyPy (GH 42355)

- `DataFrame` constructed with an older version of pandas could not be unpickled (GH 42345)

- Performance regression in constructing a `DataFrame` from a dictionary of dictionaries (GH 42248)

- Fixed regression in `DataFrame.agg()` dropping values when the DataFrame had an Extension Array dtype, a duplicate index, and `axis=1` (GH 42380)

- Fixed regression in `DataFrame.astype()` changing the order of noncontiguous data (GH 42396)

- Performance regression in `DataFrame` in reduction operations requiring casting such as `DataFrame.mean()` on integer data (GH 38592)

- Performance regression in `DataFrame.to_dict()` and `Series.to_dict()` when `orient` argument one of “records”, “dict”, or “split” (GH 42352)

- Fixed regression in indexing with a `list` subclass incorrectly raising `TypeError` (GH 42433, GH 42461)

- Fixed regression in `DataFrame.isin()` and `Series.isin()` raising `TypeError` with nullable data containing at least one missing value (GH 42405)

- Regression in `concat()` between objects with bool dtype and integer dtype casting to object instead of to integer (GH 42092)

- Bug in `Series` constructor not accepting a `dask.Array` (GH 38645)

- Fixed regression for `SettingWithCopyWarning` displaying incorrect stacklevel (GH 42570)

- Fixed regression for `merge_asof()` raising `KeyError` when one of the `by` columns is in the index (GH 34488)

- Fixed regression in `to_datetime()` returning pd.NaT for inputs that produce duplicated values, when `cache=True` (GH 42259)

- Fixed regression in `SeriesGroupBy.value_counts()` that resulted in an `IndexError` when called on a Series with one row (GH 42618)

## Bug fixes

- Fixed bug in `DataFrame.transpose()` dropping values when the DataFrame had an Extension Array dtype and a duplicate index (GH 42380)

- Fixed bug in `DataFrame.to_xml()` raising `KeyError` when called with `index=False` and an offset index (GH 42458)

- Fixed bug in `Styler.set_sticky()` not handling index names correctly for single index columns case (GH 42537)

- Fixed bug in `DataFrame.copy()` failing to consolidate blocks in the result (GH 42579)

## Contributors

A total of 17 people contributed patches to this release. People with a “+” by their names contributed a patch for the first time.

- Fangchen Li

- GYvan +

- Matthew Roeschke

- Matthew Zeitlin

- MeeseeksMachine

- Pandas Development Team

- Patrick Hoefler

- Richard Shadrach

- Shoham Debnath +

- Simon Hawkins

- Stephan Heßelmann +

- Stephen +

- Thomas Li

- Zheyuan +

- attack68

- jbrockmendel

- neelmraman +