Effective August 1, 2025, Microsoft offers a 6-month Extended Security Update (ESU) program for Exchange Server 2016 and 2019 and Skype for Business Server 2015 and 2019.
Microsoft Exchange Server 2016/2019 and Skype for Business Server 2015/2019 reach their end of support on October 14, 2025. The 6-month Extended Security Update (ESU) program can be purchased from August 1, 2025, and runs until April 14, 2026. It is intended for customers who need more time to complete their migration to supported platforms.
What does this “6-month Extended Security Update (ESU) program” mean?
- This ESU is not an “extension of the support lifecycle” for Exchange Server 2016/2019 and Skype for Business Server 2015/2019. 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 Security Update (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 Server Subscription Edition (SE) and Skype for Business Server Subscription Edition (SE) before October 14, 2025, to receive Critical and Important updates as SUs that Microsoft might release after October 2025. If there are SUs that Microsoft needs to release, they will privately provide such SUs to ESU customers. Exchange Server 2016/2019 and Skype for Business Server 2015/2019 SUs will not be released on public Download Center or Windows Update after October 2025.
- Microsoft is not committing to actually releasing any SUs during the ESU period. SUs are released only if there are Critical or Important security product changes.
- This ESU will be valid for 6 months only (through April 14, 2026). Microsoft states clearly, that this period will not be extended past April 2026.
Who is Exchange Server 2016/2019 and Skype for Business Server 2015/2019 ESU for?
This program is intended only for customers who are unable to finalize their migrations to Exchange Server Subscription Edition (SE) and Skype for Business Server Subscription Edition (SE) before end of support lifecycle for Exchange Server 2016/2019 and Skype for Business Server 2015/2019, already use Exchange 2016 CU23 or Exchange 2019 CU14/CU15 or Skype for Business Server 2015/2019, and still need Critical and Important security coverage for the older servers still in operation.
What should we do now?
We recommend that customers do not rely on this ESU and instead upgrade their organizations to Exchange Server Subscription Edition (SE) and Skype for Business Server Subscription Edition (SE) in time.
Licensing
For information related to per server cost and additional details on how to purchase and receive ESUs, contact SCHNEIDER IT MANAGEMENT after August 1st, 2025.
More information
Announcement of Exchange 2016 / 2019 Extended Security Update program:
Announcement of Skype for Business 2015 / 2019 Extended Security Update program: https://techcommunity.microsoft.com/blog/skype_for_business_blog/announcing-skype-for-business-2015–2019-extended-security-update-program/4433493
Microsoft Exchange and Skype for Business Server Subscription Editions available: https://www.schneider.im/microsoft-exchange-and-skype-for-business-server-subscription-editions/
Microsoft products retiring in September and October 2025: https://www.schneider.im/microsoft-products-retiring-in-september-and-october-2025-reminder/
For our Microsoft page, please visit: https://www.schneider.im/software/microsoft.
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