As per Lubos’ post here Unable to login to API after update - #13 by lubos, the API still works fine with the free desktop edition but without a way to set administrator password.
To set a password, use the workaround suggested by Lubos:
- Get the trial server appimage from here
Releases · Manager-io/Manager.AppImage · GitHub - Run the appimage,which starts the server
- Open a Manager instance on the server at localhost:8080
- Set an administrator password
- Desktop edition API should then work using the same password (password file was created in your database folder)