Canvas has redesigned discussions and announcements, and the old version is no longer available.
The redesigned discussions and announcements has all of the same functionality of classic discussions and announcements, with a new look and a few additional features. You can now:
Follow the instructions on the Instructure Web site.
Icons for managing your discussion are located in the Discussions section to the right of each discussion.
If there has been activity, you will see the number of unread replies on the left and total replies on the right. Click the round icon to publish or unpublish your discussion. Click the ribbon to subscribe to the discussion (only needed if you did not create the discussion). Click the three dots to manage your discussion.
The Group Discussions interface has changed slightly. The blue box with the list of Group names that is seen in Classic Discussions has been replaced by an icon at the top left that you can click to select group discussions to review. You may also sort the responses by submission time and change how you view them.
To learn more, read the vendor's documentation.