title: The client is using an unsupported version of the Socket.IO or Engine.IO protocols Error
body: <p>I'm trying to run a client an server in python using flask_socketio, socketIO_client and SOCKET.IO in a raspberry pi 4 but I'm getting the following error:</p>
  <pre><code>The client is using an unsupported version of the Socket.IO or Engine.IO protocols (further occurrences of this error will be logged with level INFO)
  192.168.1.80 - - [05/Feb/2021 18:30:41] &quot;GET /socket.io/?EIO=3&amp;transport=polling&amp;t=NTpTT-L HTTP/1.1&quot; 400 219 0.000618
  </code></pre>
  <p>These are my current versions:</p>
  <p>pi@raspberrypi:~/Desktop/EDAdataLogger $ npm list socket.io
  EDAdataLogger@ /home/pi/Desktop/EDAdataLogger
  └── socket.io@3.1.1</p>
  <p>pi@raspberrypi:~/Desktop/EDAdataLogger $ npm list socket.io-client
  EDAdataLogger@ /home/pi/Desktop/EDAdataLogger
  └── socket.io-client@3.1.1</p>
  <pre><code>python-engineio==4.0.0
  python-socketio==5.0.4
  Flask==1.1.2
  Flask-Session==0.3.2
  Flask-SocketIO==5.0.1
  </code></pre>
  <p>How can I define JavaScript Socket.IO version and Socket.IO protocol revision so everything matches according to (<a href="https://pypi.org/project/python-socketio/" rel="noreferrer">https://pypi.org/project/python-socketio/</a>) ?</p>
  <p>How can I fix this? Thank you</p>