These are the changes in pandas 1.1.5. See Release notes for a full changelog including other versions of pandas.
Fixed regression in addition of a timedelta-like scalar to a DatetimeIndex raising incorrectly (GH37295)
DatetimeIndex
Fixed regression in Series.groupby() raising when the Index of the Series had a tuple as its name (GH37755)
Series.groupby()
Index
Series
Fixed regression in DataFrame.loc() and Series.loc() for __setitem__ when one-dimensional tuple was given to select from MultiIndex (GH37711)
DataFrame.loc()
Series.loc()
__setitem__
MultiIndex
Fixed regression in inplace operations on Series with ExtensionDtype with NumPy dtyped operand (GH37910)
ExtensionDtype
Fixed regression in metadata propagation for groupby iterator (GH37343)
groupby
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)
AttributeError
SparseArray
Fixed regression in DataFrame.unstack() with columns with integer dtype (GH37115)
DataFrame.unstack()
Fixed regression in indexing on a Series with CategoricalDtype after unpickling (GH37631)
CategoricalDtype
Fixed regression in DataFrame.groupby() aggregation with out-of-bounds datetime objects in an object-dtype column (GH36003)
DataFrame.groupby()
Fixed regression in df.groupby(..).rolling(..) with the resulting MultiIndex when grouping by a label that is in the index (GH37641)
df.groupby(..).rolling(..)
Fixed regression in DataFrame.fillna() not filling NaN after other operations such as DataFrame.pivot() (GH36495).
DataFrame.fillna()
NaN
DataFrame.pivot()
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)
MultiIndex.intersection()
Fixed regression in GroupBy.first() and GroupBy.last() where None was considered a non-NA value (GH38286)
GroupBy.first()
GroupBy.last()
None
Bug in pytables methods in python 3.9 (GH38041)
Only set -Werror as a compiler flag in the CI jobs (GH33315, GH33314)
-Werror
A total of 12 people contributed patches to this release. People with a “+” by their names contributed a patch for the first time.
Andrew Wieteska
Fangchen Li
Janus
Joris Van den Bossche
Matthew Roeschke
MeeseeksMachine
Pandas Development Team
Richard Shadrach
Simon Hawkins
Uwe L. Korn
jbrockmendel
patrick