Upgrades will begin in March 2023. The upgrades will happen progressively over the month.
We expect that there will be no downtime in service during the upgrade and that users will be able to use their mailboxes as usual with no change to availability. We have addressed the most commonly asked questions in this FAQ: https://support.manageprotect.com/a/solutions/articles/44002409614
Important: to avoid any service disruption, please check the following: An autodiscover record is required for all domains using the MPexchange service. Users with Outlook 2010 will need to upgrade their version. Users with Outlook 2013 or 2016 will need to ensure that they are all the latest service pack. Users of Windows 7, Windows 8, Windows Server 2008, and Windows Server 2012 OS versions will need to verify the TLS 1.2 is turned on within the Windows settings.
Manage Protect will fully handle the upgrade to Exchange 2019, and majority of account administrators and users will not be required to do anything in preparation for this upgrade. Please refer to the above article for details.