The shortcuts located at the bottom of the folder list in Outlook 365 (Mail, Calendar, People, Notes, etc.,) moves to a narrow vertical bar on the left with some of the shortcuts, such as Notes and Folders, missing.

For now, the only fix I have found is a registry entry:

HKCU\Software\Microsoft\Office\16.0\Common\ExperimentEcs\Overrides

Add/change 32-bit Dword:

Microsoft.Office.Outlook.Hub.HubBarcollapsible = 0