Enforce New Outlook Via Intune

You can set it in Exchange Online for multiple users (https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook#enable-or-disable-the-new-outlook-for-windows-for-multiple-mailboxes) or a specific mailbox (https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook#enable-or-disable-the-new-outlook-for-windows-for-an-individual-mailbox)

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