Upgrade from Exchange 2013+O365 hybrid to Exchange 2019+O365 hybrid

Question

Hi,

My environment currently has Exchange 2013 in coexistence with O365 (Hybrid). 2 mailbox servers + 2 CAS servers. MX record pointed to third party Mail gateway which routes to On prem servers.
Looking to upgrade to Exchange 2019 to be in coexistence with O365.
Can somebody help with the planning and steps to be followed for a smooth Migration. There are indeed a lot of articles on the internet, but cant understand where to start with or how to create a plan to start the transition.
Thank you in advance.

Answer 1

@Aritra Das

You could take steps below to update;

Update Exchange 2013 to CU 21 or later for coexist with Exchange 2019: Supported coexistence scenarios for Exchange 2019

Install Exchange 2019 coexist with Exchange 2013, then migrate all Exchange on-premises mailboxes(Include arbitration mailboxes) to Exchange 2019.

Configure Exchange 2019 as Internet facing server and rerun HCW to choose Exchange 2019 as hybrid server.

Shutdown Exchange 2013, check whether there exist issue. If there doesn't exist an issue, you could uninstall those Exchange 2013 server.

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