# What’s new in 1.1.5 (December 07, 2020)

These are the changes in pandas 1.1.5. See Release notes for a full changelog including other versions of pandas.

## Fixed regressions

- Fixed regression in addition of a timedelta-like scalar to a `DatetimeIndex` raising incorrectly (GH37295)

- Fixed regression in `Series.groupby()` raising when the `Index` of the `Series` had a tuple as its name (GH37755)

- Fixed regression in `DataFrame.loc()` and `Series.loc()` for `__setitem__` when one-dimensional tuple was given to select from `MultiIndex` (GH37711)

- Fixed regression in inplace operations on `Series` with `ExtensionDtype` with NumPy dtyped operand (GH37910)

- Fixed regression in metadata propagation for `groupby` iterator (GH37343)

- Fixed regression in `MultiIndex` constructed from a `DatetimeIndex` not retaining frequency (GH35563)

- Fixed regression in `Index` constructor raising a `AttributeError` when passed a `SparseArray` with datetime64 values (GH35843)

- Fixed regression in `DataFrame.unstack()` with columns with integer dtype (GH37115)

- Fixed regression in indexing on a `Series` with `CategoricalDtype` after unpickling (GH37631)

- Fixed regression in `DataFrame.groupby()` aggregation with out-of-bounds datetime objects in an object-dtype column (GH36003)

- Fixed regression in `df.groupby(..).rolling(..)` with the resulting `MultiIndex` when grouping by a label that is in the index (GH37641)

- Fixed regression in `DataFrame.fillna()` not filling `NaN` after other operations such as `DataFrame.pivot()` (GH36495).

- Fixed performance regression in `df.groupby(..).rolling(..)` (GH38038)

- Fixed regression in `MultiIndex.intersection()` returning duplicates when at least one of the indexes had duplicates (GH36915)

- Fixed regression in `GroupBy.first()` and `GroupBy.last()` where `None` was considered a non-NA value (GH38286)

## Bug fixes

- Bug in pytables methods in python 3.9 (GH38041)

## Other

- Only set `-Werror` as a compiler flag in the CI jobs (GH33315, GH33314)

## Contributors

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