Your comments

Yes sure. I've used "ajenti-panel -v" for that test.
Ctrl+C then downgrade and again "ajenti-panel -v" to restart the test.
Hi !

Same issue for me. Don't know if you managed to solve it ? 
I've tried to downgrade websocket to 0.3.6-1 as in ajenti repository.
Stil the same error message and still waiting for the pannel...

python-gevent-socketio is now 0.3.5-rc2-1.
python-gevent-websocket was 0.9.3-1 and is now 0.3.6-1.

Server using Ubuntu 14.04 LTS 64 bits, Linux 2.6.32-042stab084.14, Ajenti 1.2.21.13 and Ajenti V 0.2.32.
Client using Ubuntu 13.3 64 bits, Linux 3.8.0-35-generic, Chromium browser 31.0.1650.63 or Firefox 26.0.