Exchange server 2013 and Microsoft 365-Hybrid mode

Question

Hi Everyone,

We intend to migrate from on-premises Exchange 2013 to Microsoft 365. Can we maintain a hybrid mode with an Exchange server 2013 and move 40-50 mailboxes to O365 for testing for up to a year? (The ultimate goal is to migrate all mailboxes to O365 over the course of several months, rather than immediately)?

In that case, can we keep Exchange Server 2013 for the hybrid channel, or do we need to upgrade to the 2019 version?

Please be advised.

Answer 1

Hello, @Amir-G

Welcome to the Microsoft Q&A platform!

Exchange 2013 supports hybrid deployments with Microsoft 365, allowing users to manage both local and cloud mailboxes during a migration, so moving 40-50 mailboxes to O365 for up to a year of testing is possible. However, since you are running Exchange 2013, make sure that the Mailbox Replication Proxy Service (MRSProxy) is enabled on the local Exchange 2013 client access server and ensure your Exchange Server 2013 is updated to the latest cumulative update (CU) to maintain compatibility and support

For more information on the migration process, please refer to Move mailboxes between on-premises and Exchange Online organizations in hybrid deployments | Microsoft Learn.

Also, since your current need is to migrate only a few dozen mailboxes, I recommend that you use the Exchange cutover method for your migration.

For the specific operation procedure, you can refer to Migrate email to Exchange Online using the Exchange cutover method in Exchange Online | Microsoft Learn.

While Exchange 2013 supports mixed mode, Microsoft typically recommends using the latest version for better support and functionality. Exchange 2013 ends mainstream support in April 2023 and enters the extended support phase, which means no more new features or non-security updates. If you plan to use mixed mode for the long term, it is recommended to upgrade to Exchange 2016 or 2019 for better performance and security. Exchange 2019 is supported through October 2025, providing a longer support cycle.

Should you need more help on this, you can feel free to post back. 

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Thank you for your support and understanding.

Best Wishes,

Alex Zhang

Answer 2

Hi Alex,

Thanks for your explanation.

What happens to 2013 CALs if we upgrade it to 2019? and what are 2019 CAL requirement? Do we need to purchase CALs for 2019?