Older plugin had no version number, so it had been treated as the newest. The new one had version number as 0.1.
The entrance is at main.py -> ChatConnection.py
try to add [code]print 'hello'[/code] at line 25 and see the result.
You might need to edit client (chat plugin) to meet server. You can reference to Zack0Wack0's socket.io, it's more clearly then mine.