by Mary Cooch.
Please see also the note in the documentation on Assignment upgrade tool (relating to restoring courses )
Note: 'Assignment 2.2' should NOT be disabled until all course backups containing assignments from Moodle 2.2 and older are restored. If this is going to take some time, to avoid the confusion of two assignments being listed in the activity chooser, the capability mod/assignment:addinstance should be removed from the roles of teacher and manager. In this way, any old assignments will appear and may be used, but teachers will not be able to create any new 'Assignment 2.2' instances.