Hi @SLAMA Nadhem ，
You can follow the steps below.
- Make sure your exchange 2013 server is updated to the latest cumulative update (CU23), then download the latest version of exchange 2019 on the new Windows server belonging to the same ad site and install the prerequisites for exchange 2019. Finally, Prepare Active Directory and complete the installation of the exchange 2019 and mailbox role.
- Next you need to configure the Exchange 2019 URL based on the namespace, configure the automatic discovery SCP for internal clients, configure the 2019 database for the default OAB, configure the Exchange 2019 certificate, and configure the connector.
- Finally, you can start to migrate your mailboxes, before that you can do some necessary tests. Examples include connecting to archive mailboxes, using public folders, and delegation scenarios. Test Outlook, Free/Busy, Outlook on the web, ActiveSync, Out of Office, and any custom or third-party applications. And after pointing SCP to Exchange 2019, you can move the arbitration mailbox, move the administrator mailbox, and move the mailbox. (Note that before doing any migration operations, please make necessary backups.)
- Turn off exchange 2013 and monitor for a week - if all good, then perform the uninstallation.
More details can be found in the link below.
Best Practices for Migrating from Exchange Server 2013 to Exchange Server 2019 - Microsoft Community Hub
This link can help you step by step according to your specific needs.
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