Exchange 2016 and 2019 End of Life Passed: Your Emergency Guide
I remember the countdown to October 14, 2025, the date when Exchange 2016 and 2019 end of life hit officially.
There was plenty of time, but still some organizations could not complete the transition on time. Now we are almost in 2026, so it has been a few months since the last security updates.
Microsoft had already predicted such a situation, so it announced the Extended Security Update. The organizations that opted for it got some extra time to move their existing Exchange Server customers. However, this program aims but does not guarantee to provide Security Updates (SU) for a limited time.
In this updated guide, I will strip away the “what if” scenarios and give you the cold, hard facts about where you stand right now.
Exchange Server 2016 and 2019 End of Life Aftermath
Let’s look at the calendar. Microsoft officially ended support for both Exchange 2016 and 2019 on October 14, 2025.
This means your server did not receive the November or December security patches.
- No Time Zone Updates: Your calendars might start acting weird soon.
- No Bug Fixes: If something breaks, Microsoft Support won’t help you unless you have a custom contract.
- High Security Risk: Many official reports, such as the recent BSI, made staggering revelations that nearly 92% of Exchange servers in Germany are unprotected. Hackers know these servers are unpatched. They are actively scanning for them right now.
What is Exchange Server Extended Security Update Exactly?
Any organization that is unable to switch over to the Exchange Server Subscription Edition (SE) on time can think of the ESU as a safety net. This will ensure that they continue to receive the Critical and Important updates (as per the MSRC score) even on the old Exchange Servers.
Microsoft has made it clear through their announcement that purchasing the ESU program does not mean that you will receive the updates.
Moreover, even if any SUs are released during the 6 months, customers won’t be able to access them directly. In other words, unlike the regular Patch Tuesday updates, there will be no publicly accessible link.
Instead, these updates will be provided privately to all organizations that choose to become ESU program subscribers. Although there is no official statement, we believe that your Microsoft Account team will be the one responsible for providing you with the security updates.
This is not the first time that such emergency extensions have been made by Microsoft. For example, when Windows 7 was expiring, it received an ESU program that lasted for up to three years(From 2020 to 2022). Even the soon-to-expire Windows 10 has an ESU package that can be bought from the Microsoft Volume Licensing Program, at USD 61 per device for Year One.
Both Windows Server 2012 and 2012 R2 (the OS on which all Exchange on-premises systems run) got a 3-year ESU pack. SQL Server 2012 also had a three-year ESU program.
When Does ESU Become Available & for How Long?
From August 1st, 2025, you can contact your Microsoft Account team and get the pricing details to deploy the Extended Security Update.
This update will last for 6 months from the date of expiry of the current systems, i.e., October 14, 2025, to April 14, 2026. Microsoft explicitly states that no further extensions or updates will be made available.
However, let me make it clear that the ESU is not a true extension of the expiry date for the on-premise Exchange Server.
Exchange Server is still on the new lifecycle policy, which means that both Exchange 2016 and 2019 are going to stop receiving official support on the pre-determined date. So you should not postpone your migration plans.
How Much Will the ESU Cost After Exchange 2016 and 2019 End of Life?
No official pricing has been revealed yet, but here’s what we know about the cost:
- It will be on a Per-Server basis. The more servers you have in your local environment, the more you have to pay.
- Organizations that need the ESU price quotation can contact their Microsoft account team on or after August 1, 2025.
- Moreover, we don’t think that a public price list will be made available.
Another important factor to keep in mind is that currently, only those organizations can get the ESU who have their Exchange Server directly from Microsoft. Customers who bought through a CSP or other reseller must wait for further announcements.
Should You Rely On ESU in the Exchange 2016 and 2019 EOL Era?
The Exchange 2016 and 2019 end of life dates have already passed. So this question becomes even more important. Microsoft recommends customers not to rely on this ESU program but instead move to the new version ASAP.
Here is the reality of ESU:
- The Clock is Ticking: This update window is strictly limited. It lasts only until April 14, 2026. That means you have less than 5 months of coverage left before the final hard stop.
- Private Access Only: Unlike regular “Patch Tuesday” updates, these are not public. If you buy the ESU, Microsoft provides these updates privately to your tenant.
- The Cost Factor: Pricing is on a Per-Server basis. Crucially, if you jump in now, be prepared for potential retroactive fees to cover the gap since October.
My Verdict: Unless you are a massive enterprise legally required to stay on-premise, chasing an ESU license now is a desperate measure. It is a Band-Aid, not a cure. You are better off putting that budget toward a permanent migration.
Since you can’t stay where you are, you have two paths forward. I help clients make this decision every day.
Stay On-Prem After Exchange 2016 and 2019 End of Life
If you simply must keep your data in your own server room, you need to move to the new Exchange Server Subscription Edition (SE). This is the new standard, but the path to get there depends entirely on your starting point.
- For Exchange 2019 Admins: If you were smart and upgraded to CU15 before October, you can likely do an in-place upgrade to SE. It’s a relatively painless code swap.
- For Exchange 2016 Admins: This is the bad news. You cannot upgrade directly via an in-place update.
In the past, you might have performed an intermediate Exchange 2016 to 2019 migration just to get ready. But with the deadline passed, that “double hop” wastes too much time and resources. You need to perform a direct Exchange 2016 to Exchange SE migration by building a new server and moving the data immediately.
For that, you can use the SysTools Exchange to Exchange Migration software, which helps to conduct a smooth, effortless transition.
Download a demo right now and try the software for free.
Jump to Office 365 after Exchange 2016 and 2019 End of Support
Honest talk? This is what 90% of my clients are doing. They are tired of the “End of Life” panic. They are moving to Exchange Online.
The Benefit: You never have to patch a server again.
The Problem: Moving terabytes of data from an unsupported, potentially vulnerable server is risky.
Yet if you use the SysTools Exchange to Office 365 migrator, you can shift with speed and security.
Conclusion
Here, we found that ESU is not a true extension to the Exchange 2016 and 2019 end-of-life date. Instead, Microsoft is offering a paid security package. Customers who can’t make the transition to the new setup before October 14, 2025, can use it to buy some time.
Moreover, those who use any of the older Exchange Server versions can’t transition to the SE edition directly. So, they can use the automated migration solution instead to fast-track their transition.
Frequently Asked Questions on Exchange 2016 and 2019 End of Life
Q: I missed the Exchange Server EOL deadline. Will Microsoft turn off my server?
A: No, unlike the cloud services, Microsoft does not possess the ability to remotely switch off your on-premises server. Your emails keep flowing as they did before the EOL. However, just because it works does not mean it’s safe. You are putting your systems at more risk every single minute you remain on an expired server.
Q. Did Exchange Server 2019 End of Life happen alongside Exchange 2016?
A: Yes, for the first time ever, Microsoft had put two different generations on Exchange Server in the EOL category at the same time. This was done to fast-track the transition to the new subscription edition model.
Q: If I buy ESU now, do I have to pay for October and November?
A: In my experience, yes. Microsoft typically requires you to buy “catch-up” licenses. You cannot just pay for the future months; you have to pay for the continuous coverage timeline, even if you buy it late.