You did not provide the most important pieces of information:
a.) Does the installation complete or does it abort throwing the error message?
b.) Does Seahub start?
Additionally, answer these two questions:
1.) Is there a gunicorn.conf in the conf folder in the Seafile’s install directory? (What are the file’s permissions?)
2.) Is there a gunicorn.conf.py in the conf folder in the Seafile’s install directory? (What are the file’s permissions?)
Given that you already encountered problems in your previous update, I’d very meticulously check my conf file if I were you. (Finally, apparently, you found a solution to your update problem because you’re not with 8.0.6. Would you be so kind and report back to the community how you solved your problem and then mark the topic as closed?)