Good morning to everyone.
I have a couple of questions that I hope you can help me resolve. These questions are related to Exchange Server 2013 (I know that this product is out of support and that is why we are migrating it to Exchange Server 2019).
This is my scenario:
I have a main site with 2 Exchange Server 2013 CU10 servers, I have a site with 1 Exchange Server 2013 CU23 server, I have another site with 1 Exchange Server 2013 CU23 server. The main idea is to migrate all mail servers to Exchange Server 2019.
These are the questions:
1. Is it possible to install a new server with Exchange Server 2019 on the main site without upgrading the remaining servers with Exchange Server 2013 to CU23?
2. What will happen to the mail flow after installing the new server with Exchange Server 2019? Will the main server with Exchange Server 2013 continue to manage the internal and external mail flow? Or will the new server with Exchange Server 2019 manage the mail flow?
3. In case the new server with Exchange Server 2019 is the one that manages the mail flow, is there a possibility that the server with Exchange Server 2013 will manage the mail flow until the migration is finished?
Thank you for your time and collaboration

​Good morning to everyone.I have a couple of questions that I hope you can help me resolve. These questions are related to Exchange Server 2013 (I know that this product is out of support and that is why we are migrating it to Exchange Server 2019).This is my scenario:I have a main site with 2 Exchange Server 2013 CU10 servers, I have a site with 1 Exchange Server 2013 CU23 server, I have another site with 1 Exchange Server 2013 CU23 server. The main idea is to migrate all mail servers to Exchange Server 2019.These are the questions:1. Is it possible to install a new server with Exchange Server 2019 on the main site without upgrading the remaining servers with Exchange Server 2013 to CU23?2. What will happen to the mail flow after installing the new server with Exchange Server 2019? Will the main server with Exchange Server 2013 continue to manage the internal and external mail flow? Or will the new server with Exchange Server 2019 manage the mail flow?3. In case the new server with Exchange Server 2019 is the one that manages the mail flow, is there a possibility that the server with Exchange Server 2013 will manage the mail flow until the migration is finished?Thank you for your time and collaboration  Read More

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