In the Outlook update released on October 10 2017, the Folder Homepages setting was deprecated and removed to close a security vulnerability. Removing the folder home page capability "broke" a lot of applications; this can be fixed by setting a registry key.
In the September 12 2017 security update, Microsoft disabled custom form script functionality. Forms with code behind them generate this error message: To help prevent malicious code from running, one or more objects in this form were not loaded. For more information, contact your administrator. If you need scripts enabled, you'll need to set two keys, one to enable scripting and a second one with the message class name of each form that has code behind it.
Office 365 training videos, covering the Office applications. Also included is a video for managing Office 365 Home and Business accounts. Downloadable guides for the main Office 2016 applications (Outlook, Word, Excel, OneNote, PowerPoint) are available.