On-premise Exchange 2016 to 2019 Migration and Co-existence

Andryszak, Daniel 116 Reputation points

I have reviewed many posts related to Exchange 2016 to 2019 migration and co-existence.
There appears to be two methods when the mailbox migration should occur.
One is after the new server is online and certificate imported, the other after all of the post-migration tasks are completed.
What is the recommended method?
Are there issues with one over the other?

Below are the steps - does anyone have more complete, detailed document?

  1. Install Exchange 2019 on new server.
  2. Update the Service Connection Point which is the record that will direct the users to the current Exchange Server.
  3. Import the certificates into the new server.

>> Start the Migration Process

  1. Redirect all URLs to point to the new Exchange Server 2019, like Offline Address Book, ECP, and others.
  2. Change the direction of all the outside ports from the Exchange Server 2016 to the IP address of the Exchange Server 2019. From the Exchange Sever PowerShell, point the SCP record to the 2019 server.

>>> Start the Migration Process

  1. Decommission the Exchange 2016 server,
Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Andy David - MVP 115.6K Reputation points MVP


    Very detailed step by step

    I would move mailboxes at anytime since 2016 can proxy to 2019 , however, after step 5 makes sense for the bulk moves. Before that you can move some testers

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  2. Andy David - MVP 115.6K Reputation points MVP

    No, you dont need to, but I would recommend you do, get it over with.

    Note that since 2016 can proxy to 2019, if they are using the same name space in load balancing, you can just have them all set to the same URLs and remove 2016 as you see fit.

    1 person found this answer helpful.

  3. Amit Singh 3,411 Reputation points

    Agree with @Andy David - MVP

    Follow the Migration Assistant to move between versions once everything has been migrated to 2019.

    In consideration of reducing the effect for the current client, install a new Exchange 2019 server in a new network side, then configure all services (include SCP, all VD's URL, Outlook Anywhere, MAPI over HTTP) and install the certificate.

    You can also check this article for help - Migrate Exchange 2016 to 2019 Safely


    Please mark as "Accept the answer" if the above steps helps you. Your suggestion will help others also !

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  4. Andy David - MVP 115.6K Reputation points MVP

    If you follow those steps in the link provided, it will show what to do:https://assistants.microsoft.com/

    Essentially, you need to ensure the client URLs and certificates on the 2019 servers match the 2016, then move mailboxes, then remove the send connector on the 2016 side.
    You didnt mention hybrid before, but if you are in a hybrid config with Exchange Online, then run the Hybrid Wizard and pick the 2019 server(s) as the new endpoint instead of the 2016, then you can remove the 2016 servers.

    Make sire the 2019 servers have the necessary firewall ports open to external (25. 443) and DNS records are updated as well.