Hi,
Sorry to wake up this old thread… We just updated from 4.4.4 to 6.3.4 and we face of the same problem.
To avoid anybody to signup, in 4.4.4 we configured (ENABLE_SIGNUP = True) but we didn’t display the signup link on the login page. In this way we limited the registration to only “invited” users.
Do you think that the “Automatically send invitation to unknown user” feature could be integrated again in future versions of Seafile as a configuration parameter or is it completely abandoned ?