Google launched a new layout to Google+ yesterday. Panels now replace the stream, and the Hangout and Talk services are being integrated. UMICH accounts do not have access to Preview features for now as we await clarification from Google on issues related to Terms of Service.
Google also launched a new Hangouts App for smartphones. Although UMICH accounts can download and install these new apps, UMICH users are unable to sign in at this time. The original Google+ mobile app continues to work.
You can still start Hangouts from within the Talk feature in M+Google Mail as well as the original Google+ mobile app (not the new Hangouts app). Refer to this support document for details. We have a support ticket open with Google and will update as we learn more. For more information, see Google's announcement.