the documentation part below, still says fast-cgi is recommended, I think this should be changed.
https://manual.seafile.com/overview/components.html
Seahub (django)：the web frontend. Seafile server package contains a light-weight Python HTTP server gunicorn that serves the website. By default, Seahub runs as an application within gunicorn. You can also configure Seahub to run under fast-cgi mode, behind Nginx or Apache. This is recommended for production setups.