Form errors show the specific problem. Discussion, poll, group, vote and comment forms now surface the actual validation error from the server (e.g. which field is invalid and why) instead of a generic "check for errors and try again" message.
Admin-only participant verification. New instance-level setting restricts the "verify participants" / voting-receipts feature to group admins only, rather than anyone who can see the poll.
Remove group logo or cover photo. Group admins can now remove an uploaded logo or cover photo from group settings, not just replace it.