For example, one reason for generating a new joining code might be that the previous code fell into the wrong hands and you don't want unwanted members to join your group.
To do this, first go to “My Groups” using the drop-down menu in the header at the top right and select the desired group from the group overview.
At this point you should be able to view the group's member list. In this view, select the “Settings” tab.
Under “General” click on the “Join Code” menu item to generate a new code.
Note: The old code then becomes invalid and is therefore considered deactivated.
All members who are already in the group are retained.