These are topics that are outside the scope of this book, but here's a brief description of each:
- Public folders are no longer supported by Outlook 2016. If your company does not already have public folders, we don't recommend that you start using them.
- Unified messaging connects Exchange Online with on-premise communication solutions such as Skype for Business Server or VOIP. Since it's primarily concerned with integrating with on-premise solutions of one type or another, it's not within the scope of this book.
- A hybrid deployment is when your organization's on-premise Exchange server is integrated with Exchange Online, such that some mailboxes are hosted in the cloud and some are on premises. Since this is heavily concerned with on-premise Exchange, it's outside the scope of this book.