When did support for Exchange 2016 and 2019 end? For both versions on October 14, 2025. Since then there have been no public security updates, no bug fixes and no Microsoft support. Microsoft ended the paid Extended Security Update (ESU) program with the last update on October 13, 2026. If you still run Exchange 2016 or 2019 today, you have three paths: upgrade to Exchange Server SE, move to Exchange Online or a mix of both. Continuing to operate without updates is not a viable solution for a mail server that is reachable from the internet.
Quick decision
| Your situation | Recommended path |
|---|---|
| Exchange 2019, your own server is to stay | direct upgrade to Exchange Server SE |
| Exchange 2016, your own server is to stay | set up new SE servers, move the mailboxes |
| Small environment with no obligation to keep data in-house | move to Exchange Online |
| Mailboxes already partly in the cloud | complete the hybrid deployment or continue it with SE |
| Exchange 2013 or earlier | act immediately; out of support since April 11, 2023 |
The dates
| Version | Available since | End of mainstream support | End of extended support |
|---|---|---|---|
| Exchange Server 2016 | October 1, 2015 | October 13, 2020 | October 14, 2025 |
| Exchange Server 2019 | October 22, 2018 | January 9, 2024 | October 14, 2025 |
| Exchange Server SE | July 1, 2025 | continuous | no fixed date, December 31, 2035 at the earliest |
Exchange 2019 thus received just under seven years of support, considerably less than the usual ten. Microsoft did not extend the deadlines.
What the end of support means in practice
- No security updates. Newly discovered vulnerabilities in Exchange 2016 and 2019 are no longer fixed. Microsoft has announced that it will no longer test these versions for vulnerabilities and will no longer name them in security advisories. According to Microsoft, this expressly does not mean that they will be spared from future vulnerabilities.
- No Microsoft support. Microsoft no longer accepts support requests for these versions.
- The server keeps running. Nothing was switched off on the cutoff date. Mailboxes, calendars and mail flow work as before.
- The time for coexistence is running out. Exchange Server SE CU3 Setup, announced for 2027, cannot be installed as long as Exchange 2016 or 2019 is present in the organization.
The ESU program has ended
For latecomers, Microsoft had offered two periods with extended security updates:
| Period | Duration | Status |
|---|---|---|
| Period 1 | October 2025 to April 14, 2026 | expired |
| Period 2 | May 2026 to the end of October 2026 | expired; last update on October 13, 2026 |
Microsoft has ruled out a further extension. The program was never an extension of support: it only comprised security updates rated critical or important for Exchange 2016 CU23 and Exchange 2019 CU14 or CU15, which Microsoft provided to the participants non-publicly.
Path 1: upgrade to Exchange Server SE
Starting point Exchange 2019. With CU14 or CU15 you install SE directly over the existing installation, like a cumulative update. You first bring older builds to CU15. The first release of SE technically corresponds to Exchange 2019 CU15; the risk is correspondingly low.
Starting point Exchange 2016. There is no direct update. The steps:
- Bring Exchange 2016 to CU23, if not done yet.
- Provision new servers with Windows Server 2019, 2022 or 2025.
- Install Exchange Server SE into the existing organization.
- Move mailboxes, public folders and connectors to the new servers.
- Uninstall Exchange 2016 before SE CU3 is due.
Microsoft advises against still setting up Exchange 2019 as an intermediate step now.
Licenses. For SE, Microsoft requires server licenses and CALs with active Software Assurance or qualifying cloud subscriptions for all users. Older licenses without Software Assurance are not sufficient for this. The details are in the guide
Exchange Server SE: what changes.
Path 2: move to Exchange Online
The mailboxes move to Microsoft’s cloud service. Hardware, the Windows Server license and the server’s updates are no longer needed; in return you pay an ongoing fee per user. For small environments without special requirements, this is often the path with the least effort. Microsoft offers Exchange Online as separate plans (Plan 1 and Plan 2). What distinguishes purchase and subscription for Office is shown in the guide
Office 2024 or Microsoft 365.
Path 3: hybrid deployment
Some of the mailboxes are in Exchange Online, some on-premises. For this too, the on-premises server must be supported, i.e. SE. For servers that only serve to manage recipients, Microsoft continues to provide a free hybrid license. It does not apply to servers that host mailboxes or work as a mail relay.
Typical cases
Medical practice, 9 mailboxes on Exchange 2016. The server is eleven years old, and nobody maintains it regularly. Here the move to Exchange Online is the obvious path; a new server with SE, Software Assurance and a Windows Server license would be a lot of effort for nine mailboxes.
Mechanical engineering company, 120 mailboxes on Exchange 2019, CU15. Line-of-business applications send through the on-premises server, and the data is to stay in-house. The direct upgrade to SE takes about as long per server as a cumulative update. Clarify the licensing question beforehand.
Municipality, 600 mailboxes on Exchange 2016. New servers, migration and licenses with Software Assurance need lead time for procurement and testing. Start planning now; the old servers must be removed before SE CU3.
Is it still worth buying CALs for 2016 or 2019 now?
Only in one case: you continue to run the old version for a clearly limited transition period and have to license individual new users or devices. For a new environment, these versions are no longer the right basis. The difference between the CAL types is explained in
Exchange CAL Standard or Enterprise.
At VivaKeys
We do not carry the Subscription Edition, neither server licenses nor CALs. We carry client access licenses for the two previous versions. Their support has expired; they only make sense to extend an existing environment for the transition period:
- Exchange Server 2019: Standard 1 User CAL, Standard 1 Device CAL
- Exchange Server 2016: Standard 1 User CAL, Standard 1 Device CAL
All offers are in the
Exchange Server category. If you are not sure what fits your environment, write to us with the server version, number of mailboxes and existing agreements. You will find the support dates of the other Microsoft products in the
end-of-support calendar, the licensing rules of the database in the guide
Licensing SQL Server: per core or server + CAL.
Frequently asked questions
When is the end of support for Exchange 2019? Extended support ended on October 14, 2025, mainstream support already on January 9, 2024. Exchange 2016 expired on the same day.
Are there still extended security updates for Exchange 2019? No. The ESU program ran in two periods until October 2026. The last update was released on October 13, 2026; Microsoft has ruled out a further extension.
Can I simply keep running Exchange 2016 or 2019? Technically yes, the server continues to work. However, it no longer receives security updates. For a mail server that is reachable from the internet, this is a considerable risk.
Can I switch directly from Exchange 2016 to Exchange Server SE? Yes, but not as an update of the existing installation. You install SE on new servers in the same organization and move the mailboxes.
Are my Exchange Server 2019 CALs valid for Exchange Server SE? Only if they are covered by active Software Assurance. Without Software Assurance you need new CALs with Software Assurance or qualifying subscriptions for SE.
Do I have to set up the mailboxes again after the upgrade to SE? Not with the direct upgrade from Exchange 2019; it behaves like a cumulative update. When migrating from Exchange 2016, the mailboxes are moved to the new servers, and the content is retained for the users.
Sources
Checked on 2026-11-10 against the publisher’s information:
- learn.microsoft.com/en-us/lifecycle/products/exchange-server-2019
- learn.microsoft.com/en-us/lifecycle/products/exchange-server-2016
- learn.microsoft.com/en-us/lifecycle/products/exchange-server-subscription-edition
- techcommunity.microsoft.com/blog/exchange/upgrading-your-organization-from-current-versions-to-exchange-server-se/4241305
- techcommunity.microsoft.com/blog/exchange/announcing-exchange-2016–2019-extended-security-update-program/4433495
- techcommunity.microsoft.com/blog/exchange/announcing-period-2-exchange-20162019-extended-security-update-esu-program/4511603
- techcommunity.microsoft.com/blog/exchange/exchange-server-subscription-edition-se-is-now-available/4424924
- www.microsoft.com/en-us/microsoft-365/exchange/microsoft-exchange-licensing-faq-email-for-business
- learn.microsoft.com/en-us/exchange/plan-and-deploy/supportability-matrix