Thanks for the help from Humboldt University Berlin and Johannes Gutenberg-Universität Mainz, a new Seafile forum for educational users/customers is ready.
It is currently hosted as a Moodle course at HU Berlin: https://moodle.hu-berlin.de/course/view.php?id=67467
This forum provides a communication platform for educational users of
the Seafile and their specific requirements. You can get a direct contact to the
developers of the Seafile software.
It is currently invitation only. You can send an email to firstname.lastname@example.org if you’d like to join.