I am using "the latest" "influxdb_client" and "the latest" "pandas" (and python 3.8)
$ python3 -m pip show pandas
Name: pandas
Version: 1.4.1

When running code, I get a warning message in my output:
/home/jupyter/.voila_env/lib/python3.8/site-packages/influxdb_client/client/flux_csv_parser.py:
190: FutureWarning: The frame.append method is deprecated and will be removed from pandas in a future version. Use pandas.concat instead.
line 190: return self._data_frame.astype(_temp_df.dtypes).append(_temp_df)

Mitigation attempt: I changed influxdb_client/client/flux_csv_parser.py line 190
# Append data
return self._data_frame.astype(_temp_df.dtypes).concat(_temp_df)
Alas, this did not solve the problem. Instead, I had this execution error:
AttributeError: 'DataFrame' object has no attribute 'concat'

I'd welcome any advice or update. I'll probably spend some time on this before I pull pandas back down to an earlier release.
Thanks