Annonced in the 2.2.0 release. Chained assignments will also no longer work.<p>There is a migration guide [0].<p>0: <a href="https://pandas.pydata.org/pandas-docs/version/2.2.0/user_guide/copy_on_write.html#copy-on-write-migration-guide" rel="nofollow">https://pandas.pydata.org/pandas-docs/version/2.2.0/user_gui...</a>