Open some forum where you have old discussions Set lockdiscussionsafter to something small Create a course Create a forum activity in the course Create a discussion in the forum View the forum table in your database (called mdl_forum if you're using mdk) Update the lockdiscussionafter column and set it to 1 instead of 0 (this will lock the discussion 1 second after it's created). View discussion as a student and make sure the warning about discussion being locked is displayed in a notification box