The latest change observed, an Office 365 Groups icon has appeared in the global menu which appears to launch a Groups notification panel. It’s available in OneDriveFB, Delve, Sites, portal.office365.com. While in OWA, your notifications will appear as email notificaitons, so there’s no need for the panel to display. But we may see this change.
There is a reference to the notifications panel in the Office 365 Roadmap. It will be used for other things; “…system alerts like password expiration, new emails, calendar reminders and eventually group likes”
See these Roadmap references:
Join the discussion on the Office 365 Network at https://www.yammer.com/itpronetwork/groups/changealerts