Exchange Server 2016 and 2019 End of Life – Upgrade or Move to Cloud?

If you’re still using Exchange Server 2016 or 2019, it’s time to prepare for a major change. Both versions will reach the End of Support on October 14, 2025. I’ve been helping organisations with Exchange upgrades and migrations for years, and I know how critical it is to plan early. 

In this guide, I’ll explain what Exchange Server 2016 and 2019 end-of-life means and what steps you should take next.

What Does End of Life Mean for Exchange Server?

End of Life (EOL) or End of Support (EOS) means Microsoft will stop:

• Releasing security updates or patches
• Providing bug fixes or feature updates
• Offering technical support (including paid support)
• Guaranteeing compatibility with other Microsoft products

Running Exchange after its End of Support leads to security risks, compliance violations, and operational disruptions. I’ve seen organizations face major vulnerabilities because they delayed migrations.

Why You Should Start Planning Now?

I always advise starting migration planning at least a year. Here’s why:

• Long planning cycles for complex environments
• Hardware upgrades or virtualisation requirements
• Training needs for new systems
• Regulatory compliance deadlines

If you’re in a regulated industry like finance or healthcare, running unsupported software could even lead to fines or audit failures.

Introducing Exchange Server Subscription Edition (SE)

Exchange Server SE is the replacement for Exchange Server 2019 and represents Microsoft’s modern subscription-based model for on-premises Exchange.

Here’s what I know so far based on Microsoft’s announcements:

• Not yet released as of June 2025
• Will replace Exchange Server 2019 for on-premises deployments
• Requires active Software Assurance (SA) or subscription licensing
• Will receive ongoing updates under the Microsoft Modern Lifecycle Policy

While Exchange SE will offer a better upgrade experience, you can’t in-place upgrade to SE from Exchange 2016. This brings us to the most important planning part.

Upgrade Paths: What Should You Do?

Based on Microsoft’s official guidance, here’s the recommended path depending on what version you’re running:

If You’re Running Exchange Server 2019:

Stay up to date with Cumulative Updates (CUs). When Exchange Server SE becomes available, you’ll be able to perform an in-place upgrade to SE.

If You’re Running Exchange Server 2016:

You cannot perform an in-place upgrade to Exchange SE from Exchange 2016. Here’s what Microsoft recommends:

1. Perform a legacy upgrade from Exchange 2016 to Exchange 2019 now.
2. Once you’re running Exchange 2019 CU12 or later, you can do an in-place upgrade to Exchange SE when it’s released.
3. While Microsoft technically allows a legacy upgrade from Exchange 2016 directly to SE RTM (when available), I don’t recommend it unless your environment is very small. Why?
   • There are fewer than 4 months between the expected release of Exchange SE and the EOS of Exchange 2016, making that a risky move for larger deployments.

What About Moving to Microsoft 365?

Many organisations are migrating fully to Exchange Online in Microsoft 365 for:

• Reduced maintenance
• Greater scalability
• Advanced security
• Hybrid configurations (if you need gradual migration)

I help clients set up hybrid deployments when they want to transition in phases rather than all at once. If your organisation is planning to migrate its Exchange Server environment to Office 365, then I highly recommend the SysTools Exchange to Office 365 Migration Tool. 

Download Now Purchase Now

This solution is best for bulk migration of data in minimal time. As I migrated my 10 TB of data for my organisation, it was easily migrated in two weeks. With this tool in hand, you can easily migrate Exchange 2010 to 2019, as well as you can upgrade Exchange 2013 to 2016 version. Before undergoing any migration project, you should follow a complete migration checklist to eliminate any chances of errors.

My Recommendations – What I’m Advising My Clients

1. Start Planning Now: Don’t wait for the latest version of Exchange.
2. Evaluate Your Needs:
   • On-premises required? Exchange Server SE
   • Cloud-ready? Exchange Online (Microsoft 365)
3. Check Current Environment: Upgrade Exchange 2016/2019 to the latest CU before any migration.
4. Review Licensing: Ensure you have Software Assurance for Exchange SE.
5. Conduct Pilot Tests: Always test migrations before going live.

Final Thoughts

I’ve guided multiple migrations over the years, and one thing I’ve learned: early planning saves time, money, and stress. With October 14, 2025, getting closer, now is the right time to start upgrading to Exchange Server SE or planning your cloud migration.

If you need help or have questions about your specific setup, I recommend reaching out to a Microsoft Certified Partner.