Hi, I installed months ago an older version of freichat in my joomla site. I remember having to manually inserting code in one php document, but i don´t remember what was the file i modified. I´m using yoothemes template yoo planet.

Any suggestions on how to upgrade?

I´ve looked for documentation but can´t find it and readme file in the downloaded package doesn´t mention upgrade process.

Best regards

the code that you copy pasted will be inside the template directory.
just use a good code editor, and search the whole template directory for the word "freichat". This way you will be able to pinpoint the file.remove that code and your done.
Now install the new FreiChatX, your old table structure will automatically be updated to the new one.