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Exchange Team Blog
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Announcing Exchange 2016 / 2019 Extended Security Update program

The_Exchange_Team's avatar
The_Exchange_Team
Platinum Contributor
Jul 15, 2025

With both Exchange 2016 and 2019 going out of support in October 2025, we have heard from some of our customers that they have started their migrations to Exchange Subscription Edition (SE) but might need a few extra months of Security Updates (SU) for their Exchange 2016 / 2019 servers while they are finalizing their migrations.

We are announcing that we now have a solution for such customers. Starting on August 1st, 2025, customers can contact their Microsoft account team to get information about and purchase an additional 6-month Extended Security Update (ESU) for their Exchange 2016 / 2019 servers. Your account teams will have information related to per server cost and additional details on how to purchase and receive ESUs, starting August 1st, 2025.

What does this mean?

  • This ESU is not an “extension of the support lifecycle” (Microsoft Lifecycle Policy | Microsoft Learn) for Exchange 2016 / 2019. Those servers still go out-of-support on October 14, 2025, and you will not be able to open support cases for them (unless directly related to an issue with a SU released to ESU customers during the ESU period).
  • This ESU is a way for customers who might not be able to finalize their migrations to Exchange SE before October 14, 2025, to receive Critical and Important updates (as currently defined by Microsoft Security Response Center (MSRC) scoring) as SUs that we might release after October 2025. If there are SUs that we need to release, we will privately provide such SUs to ESU customers. Exchange 2016 / 2019 SUs will not be released on public Download Center or Windows Update after October 2025.
  • We are not committing to actually releasing any SUs during the ESU period. Exchange Server does not necessarily receive SU updates every month on Patch Tuesday (2nd Tuesday of the month) as SUs are released only if there are Critical or Important security product changes. Therefore, if there are no SUs that we need to release during the time of ESU, there will be no such updates provided. We will, however, confirm with ESU participants each Patch Tuesday whether an SU was provided or not.
  • This ESU will be valid for 6 months only (through April 14, 2026). This period will not be extended past April 2026 (you do not need to ask).

Who is Exchange 2016 / 2019 ESU for?

This program is intended only for customers who are unable to finalize their migrations to Exchange SE before end of support lifecycle for Exchange 2016 / 2019, already use Exchange 2016 CU23 or Exchange 2019 CU14/CU15, and still need Critical and Important security coverage for the older servers still in operation.

Please continue migrating to Exchange SE in time instead of taking advantage of this ESU program. But if you really must, please contact your Microsoft account team for more details starting August 1st, 2025.

A similar program is available for our Skype for Business 2015 / 2019 customers. Please read more here.

The Exchange Server Team

Updated Jul 15, 2025
Version 1.0

24 Comments

  • Kostic's avatar
    Kostic
    Copper Contributor

    How to buy this 6-month Extended Security Update (ESU) for their Exchange 2016 / 2019 servers?
    through Microsoft directly? is there any contact No. Microsoft Switzerland or homepage?

    how look the process? 

  • lptl's avatar
    lptl
    Copper Contributor

    Our Exchange 2016 to M365 migration is delayed for technical reasons. Our provider says we’re not eligible for ESU (no Enterprise Agreement, and too small to get one), leaving Exchange 2019 as the only option. We want to avoid a double migration and are confident we can complete the M365 move by year-end if we can bridge the gap.

    Context: 1,100 mailboxes, ~800 M365 E5 licenses already committed for 3 years.

    Any solution on how to get an ESU? Thank you!

  • SebastianGrigg's avatar
    SebastianGrigg
    Copper Contributor

    Does anybody know what will happen to Hybrid Topoligies? If a customer still have Exchange 2016/2019 running in a hybrid deployment, what will happen after the "normal" EOL date? Do they run into throttling? Or worse? and if so, is it still possible to pause it for 30 days? Would be great if anybody has an official statement. 

    • Nino_Bilic's avatar
      Nino_Bilic
      Icon for Microsoft rankMicrosoft

      We do not plan to throttle a "fully up to date" Exchange 2016/2019 immediately starting end of support, no. The throttling / blocking is to address persistently vulnerable servers (servers that are out of date significantly). We do not have "a date" when we would start throttling those versions after they go out of support as that depends on vulnerabilities found / updates released. And yes, you'll still have the usual time to pause the throttling / blocking.

      • Norb_Kron's avatar
        Norb_Kron
        Copper Contributor

        Hello, please let me ask again to clarify. We have at the moment a hybrid environment exchange 2016 cu23 with office 365.

        This won´t stop to work after 25 oct 2025? because of a lot of mailboxes, we cant move all of them before this date to a new server or to the cloud.

        will it stop to work, when cu2 of exchange 2019 se will be released? cu1 seems to be no blocking reason, when i am reading this arcticle correctly.

  • nathanTCSI's avatar
    nathanTCSI
    Copper Contributor

    We reached out to our normal Microsoft distributor to ask for ESU pricing for exchange 2016 and were told that they won't have pricing until very near to the October deadline.  This article seems to imply that we should be able to get pricing anytime after August 1st.  Can we get confirmation that the SKUs for the purchase have been made available to distributors?

    • Nino_Bilic's avatar
      Nino_Bilic
      Icon for Microsoft rankMicrosoft

      Exchange 2016/2019 ESU is only available from Microsoft directly, via customer's account team.

      • nathanTCSI's avatar
        nathanTCSI
        Copper Contributor

        Just an update on this.  We have reached our account team but they have been unable to provide any further details.  They claim that they are still waiting for Microsoft to release SKUs.

  • vargeloglu's avatar
    vargeloglu
    Copper Contributor

    Although Microsoft has stated that only issues related to newly released Security Updates (SUs) will be supported, it may not be realistic for organizations to complete the transition to Exchange Server SE within just a few months. During this transition period (or even in cases unrelated to the transition), some environments may face challenges that require direct intervention.

    Will there be a roadmap for customers to provide feedback and receive support in such cases?

    • Nino_Bilic's avatar
      Nino_Bilic
      Icon for Microsoft rankMicrosoft

      It goes somewhat like this:

      • If the issue reproduces on an Exchange SE server, then it will be solved with Exchange SE server in mind, and that will be the path forward (you might be able to implement the same solution on then unsupported version). If the organization does not have an Exchange SE server, they will need to upgrade.
      • If the issue is related to a migration to Exchange Online or Exchange SE, then support will provide reasonable amount of assistance.

      But generally speaking - for other kinds of issues (configuration etc.) it will be community based support using whatever online resources we have (there are no plans to retire Exchange 2016/2019 documentation, articles or any tools in the immediate future).

  • Shivam007's avatar
    Shivam007
    Copper Contributor

    Hi, can a customer who is covering the on-premise installation of Exchange server via M365 E3/E5 license purchase ESU even if they have not maintained SA?

    • Nino_Bilic's avatar
      Nino_Bilic
      Icon for Microsoft rankMicrosoft

      ESU purchase is not tied to other licensing states. If you have a Microsoft account team, you'll be able to talk to them and get the ESU.

      • jhtuttle76's avatar
        jhtuttle76
        Copper Contributor

        I work for a Microsoft Partner, and we are getting many questions around how clients can purchase the ESU offering.  Since it appears to be a Microsoft direct engagement, what if the client doesn't have an assigned MS Rep or doesn't know who it is?

  • rhelm2024's avatar
    rhelm2024
    Iron Contributor

    Are these programs strictly for customers that have a Microsoft account team? Is there a procedure for customers who bought through a CSP or other reseller?

    • Nino_Bilic's avatar
      Nino_Bilic
      Icon for Microsoft rankMicrosoft

      We do not have such a program at this time, no. We are exploring the possibility, but no promises.

      • MisterWolf18's avatar
        MisterWolf18
        Copper Contributor

        Just to confirm then by stating things in another manner - the ESU program is not available for SMB customers. Correct?