Prepare for Exchange Server 2016 and 2019 end of life

Exchange Server 2016 and 2019 are reaching their end of life soon. If you’re still on-premises, the time to prepare is now.

We’re less than a year from the Exchange 2016/2019 end of life (EOL) date, which is set to October 14, 2025. It’s high time to plan on how you want to handle the soon-to-be-unsupported and hence non-secure versions and where to go.

A few words about Exchange Server lifecycle

If you’ve never heard about terms like mainstream support vs extended support or Exchange support matrix, I’ll dish out some basics.

Exchange support matrix aka Exchange Server supportability matrix provides information on the supported Exchange Server versions together with underlying Windows Servers they should be deployed on and which email clients are officially supported. You can find the matrix here.

In short, there are three support phases in Exchange Server 2016 & 2019 lifecycle (like with any other Microsoft Exchange Server that follows the Fixed Lifecycle Policy):

Mainstream Support – this is when your server is fully supported, so it receives regular bug fixes, security updates (SU) and new features with cumulative updates (CU). Although we’ve seen that the “new features” part has been mainly the Exchange Online’s domain for some time now. During the mainstream support, you, as the Exchange Server admin, can request changes and new features, report bugs that you’ve identified, as well as contact Microsoft’s support team. This period lasts 5 years after the release of a given Exchange Server version. For 2016 and 2019 Exchange it’s history.
Extended Support – in this next period, you can count only on the security patching. Quarterly Cumulative Updates (CU) become history, just like any hopes for new features. Both Exchange Server 2016 and Exchange Server 2019 are currently in the Extended Support phase.
Beyond the End of Support – it’s called end of life for a reason. This is when Microsoft no longer supports a given Exchange version. With no more security updates on the horizon (unless a critical vulnerability is identified), continuing the use of such a version introduces constant risks. In case of any problems, you need to resort to using your own “street-smarts” or cry for other admins’ help. The volume of threads on various tech communities (and, not to brag, the comment section on some of my articles) is living proof that maintaining a secure server after its end of life is increasingly difficult. Exchange 2016 & Exchange 2019 enter this phase on October 14, 2025.

What are your Exchange Server upgrade or migration options?

Email is one of the crucial company assets that holds precious and confidential business information. That’s why you shouldn’t ignore the news about the Exchange Server end of life. Depending on your environment and company policies, less than a year might be cutting it short. You should start planning your upgrade or migration route now to make sure your company data stays safe. There are two most obvious escape routes:

Upgrade to Microsoft Exchange Server Subscription Edition (vNext)
Migrate from Exchange Server to Microsoft 365 (Office 365)

Upgrade to Microsoft Exchange Server Subscription Edition (vNext)

If you want to continue using on-premises infrastructure provided by Microsoft, Exchange Server Subscription Edition (SE) is the only available upgrade path. Let’s quickly browse through its pros and cons:

Familiar solution
Full control over data stored locally (security and compliance-related reasons)
No fixed date for end of life – vNext has been advertised as the last Exchange Server version which you’ll get support for, as long as you’re a subscriber. If it comes to an end, after all, you’ll get a heads-up at least 12 months before the support ends.
An easy in-place upgrade from Exchange Server 2019 (that’s new for on-premises Exchange migration)
Little information at the moment (unknown pricing, no public demo available)
Change of pricing policy – it’s no longer a one-off payment but an ongoing commitment
Necessity to upgrade scripts (switch to the Admin API that uses Exchange Online cmdlets)

Learn more about Exchange Server Subscription Edition (vNext)

Migrate from Exchange Server to Microsoft 365 (Office 365)

This path is for those who have postponed their migration to the cloud, but don’t have their hands tied by policies and compliance reasons. Now that one of the reasons for staying on-premises no longer applies (licensing model change), the decision might be easier.

Here’re the pros and cons of going 100% cloud:

Access to the latest features from Microsoft
Updates, including security updates, done automatically by Microsoft
Lower costs of infrastructure maintenance
Less complex environment
Highly secure Microsoft servers in Azure
Company data stored externally, beyond company control (which can be remediated with a reliable backup solution)
Dependency on Microsoft infrastructure health and support team
Subscription pricing model requires an ongoing commitment (it’s the same for Exchange Server SE, though)
Full-scale migration required – either with the native, scripting-intensive methods or through third-party solution like CodeTwo Office 365 Migration that uses easy Next-Next-Finish wizards.