Hiya,
We use the onetopic course format a lot but I can't get out test install of 3.9 to use it. When I add the plugin the installation process will 'freeze' at the stage I get the success window. I have full debug on and I get no error messages. I have to remove the folder from our Moodle code before I can do anything with Moodle again.
Thank you,
Nige.