Incompatibility protobuf 4.X.Y with Python < 3.7

Collecting protobuf (from motorcortex-python==0.20.16)
  Downloading https://files.pythonhosted.org/packages/6c/be/4e32d02bf08b8f76bf6e59f2a531690c1e4264530404501f3489ca975d9a/protobuf-4.21.0-py2.py3-none-any.whl (164kB)
    100% |████████████████████████████████| 174kB 29.8MB/s 
protobuf requires Python '>=3.7' but the running Python is 3.6.9

Worked-around with adding specific protobuf version at install. For example: pip3 install protobuf==3.19.1 motorcortex-python==0.20.16

Issue also occurs when installing motorcortex-python-tools