It is always a good practice to plan ahead any migration so as to avoid unnecessary struggle and challenges that might occur at the last minute. With Exchange Server 2016 and Exchange Server 2019, this can be a very tricky situation as both Exchange Servers will be going out of support and end of life on the 14th of October 2025. The only option for upgrade is Exchange Server Subscription Edition (SE). In this article, we will give you insights and guidance on planning strategies and migration options to migrate to Exchange Server Subscription Edition.
Things to Consider before the Migration Projects
Planning ahead would not just include deciding on the version but there are a lot of things to take into consideration from technical, users, compliance, and company regulations perspective. First, you need to establish the version of Exchange Server that you would go for and the timeline. If you would upgrade to Exchange Server Subscription Edition (SE), you would need to invest in new hardware, storage expansion, and network load. Moreover, such move would also involve discussions with vendors to determine if the current hardware and operating system are compatible. You should also check the compatibility of the current backup solution with the new Exchange Server.
What will Exchange Server Subscription Edition (SE) bring?
The Exchange Server Subscription Edition (SE) will be the first step by Microsoft to consolidate the Exchange Server in a subscription model where you would receive continuous updates and feature upgrades, without the need to install a new version. Some of the core features of Exchange Server SE include:
- No more major version updates, except the usual Cumulative Updates (CU).
- Migration is made simpler and smoother with the current version of Exchange Server Subscription Edition (SE) has the Exchange Server 2019 as its core.
- Modern Security standards supporting protocols, such as TLS 1.3, modern authentication, and OAuth 2.0.
- Licensing is made easy by having a subscription of the Exchange Server. For the User Access Licenses (CAL), there is option to either purchase using the traditional way or opt for cloud licenses, such as Office 356 E3, E5 and other cloud options.
Recommended Path to Choose for Migration to Exchange Server SE
Although the Exchange Server Subscription Edition (SE) was released in July 2025 with coexistence with Exchange Server 2019 and 2016, the first Cumulative Update will be released in October. After this, there will be no coexistence allowed. So, if you act now, there is still a chance of smooth migration to the new version.
The first step in migration is planning as it’s crucial for the success of the project. Depending on the size of the infrastructure and complexity of the current setup, you must evaluate the below common factors:
- Hardware support
- Operating system compatibility
- Backup software availability
- User software compatibility
- Resilience and high availability requirements
Taking Stock
Once this is complete, you should take stock of the hardware, software, and the setup. This exercise would also need to be done on the data to ensure a clean and smooth data migration and reduce the migration time by not moving unnecessary mailboxes, orphaned users, or databases.
Preparation Work
Here is where you would need to look at the old and the new setup to ensure that the current Exchange Server is fully updated before proceeding with the migration.
The next step is to have the go-ahead from all the stakeholders, the staff, and the management, and have an agreement regarding the maintenance window to ensure that the operations are not affected.
Pre and Post Checks
During the operation, you should list all the project tasks to ensure that every step is completed – installation, configuration, and movement of data. Also, test all the functionalities, including server access, machines, and other services that relay through the server.
Data Migration Considerations and Challenges
During data migration, there are several challenges that you can face, such as:
- Limited coexistence
- Mailbox migration bottleneck
- In-place upgrade limitations
- Third-party integrations
This can lead to possible data loss, delays, loss of business, and downtime. You can overcome such challenges and make the migration smoother and seamless with specialized third-party Exchange migration tool, such as Stellar Migrator for Exchange. Where native tools lack, this tool offers seamless migration of primary mailboxes, public folders, and user archives to an Exchange Server, Office 365, and vice-versa, as well as migration from one tenant to another.
Conclusion
Whatever be the setup, you should ensure that the email system is future proof. In the case of Exchange Server 2016/2019, you must act now before it is too late for a seamless migration. Starting late will reveal a lot of teething issues as well as various point of failures, possible data loss, and other repercussions. One thing to add when it comes to planning a migration is to make use of professional Exchange migration software, like Stellar Migrator for Exchange that can help to achieve a reliable and safe data migration.
He is a cyber security and malware researcher. He studied Computer Science and started working as a cyber security analyst in 2006. He is actively working as an cyber security investigator. He also worked for different security companies. His everyday job includes researching about new cyber security incidents. Also he has deep level of knowledge in enterprise security implementation.
