I needed to delete the old vanilla/settings controller
After migrating my forum from Vanilla 2.8 to 3.3, the forum works fine.
But I had a problem with the dashboard. Several links in the Dashboard were opening the same page which is the kind of categories administration.
After several hours, I found that the routing engine is confused because there are two controllers named "settings" : "dashboard/settings" and "vanilla/settings". In the new version (before copy the directory in my in production directory), the second seems to be renamed to "vanilla/vanillasettings". I deleted the vanilla/class.settingscontroller.php and all the dashboard seems to work fine.
I post this message to learn where is the error. Is a lack of Vanilla upgrade script ? Or do I forgot a step in the upgrade ?