Beginning in mid-February 2022 through the end of February 2022, Microsoft is going to make the New Outlook for Mac the default experience.
You can currently turn the new experience on and off with the toggle switch in Outlook for Mac (In some versions you can enable the legacy version by going to ‘Help > Revert to Legacy Outlook’):
After Microsoft makes the change available, you may need to add some of your shared folders to the new view by following these steps:
Open shared mailbox in new Outlook experience on Mac:
In the Tools menu, choose Accounts, and select your account
Select ‘Advanced’
Select Delegation and Sharing
Choose ‘Shared With Me’ tab
Choose + to add a shared or delegated mailbox
The shared mailbox will then show up in your new Outlook for Mac.
If you have any questions or if you any problems with this new experience, please reach out to our Email Services team by opening a ticket.
More information about the New Outlook for Mac can be found here: New Outlook for Mac (microsoft.com).