Outlook 2013 introduced the concept of hybrid mode (sometimes called Exchange Fast Access) to allow clients configured in cached Exchange mode to fetch data direct from the server when possible. The mode works well, except when you’re connected on a poor network as the attempts to fetch data from the server might cause Outlook to hang. A registry setting gives a way to force Outlook to operate in classic cached mode and use the OST exclusively when it needs data.
Microsoft has implemented a new synchronization mechanism in Outlook ProPlus to deal more efficiently with shared folders. The new approach increases the limit from 500 to 5,000 folders and is a more elegant and precise solution. Users who manage other peoples’ mailboxes will appreciate the change after they install build 11629.20196 or later.
Despite the age of the protocols, you can cheerfully connect a wide range of IMAP4 and POP3 clients to Exchange Online. If you do, you might need to consider how to handle calendar appointments, and if you want to use iCAL, you’ll need to make some adjustments with PowerShell.
Outlook Mobile clients can now schedule Teams meetings, even if your tenant isn’t using the newer version of Outlook’s mobile connection architecture. The Office 365 tenant setting for Skype for Business Online co-existence mode has to be configured to use Teams, and once everything is in place Outlook is happy to schedule Teams meetings.