Table of Contents
Why Should You Act Fast? The Critical Truth About ESU for Microsoft Servers
Exchange Server 2016 and 2019, and Skype for Business 2015 and 2019, will no longer get standard updates or support after October 14, 2025. If you still use these programs after that date, your servers could become open to harm. To help, Microsoft offers Extended Security Updates (ESU). This gives you six more months of safety, but only for a fee and under clear rules.
Main Points for Administrators
- Support Ends: Normal support for all these server products stops on October 14, 2025.
- ESU Option: Starting August 1, 2025, you can purchase a six-month ESU for each server—helping you cover the time needed to migrate to the new Subscription Edition (SE).
- Private Updates: Updates (security only) will be shared privately with those who pay for ESU. They will not appear on public download sites after October 2025.
- No Full Support: You cannot open general support cases. Only problems caused by an ESU security update may get special help.
- No Extension Beyond Six Months: The ESU program ends forever on April 14, 2026, with no extra extensions possible.
- ESU for Critical Needs: ESU is not a full solution. Use it only if you cannot switch to Subscription Edition in time.
- No Promises of Updates: Microsoft won’t promise there will be security updates every month. Updates only arrive if new critical or important bugs are found.
What Must You Do Next?
- Check Your Servers—Are you running Exchange Server 2016/2019 or Skype for Business 2015/2019?
- Plan Your Move—Begin making plans to upgrade to the new Subscription Edition right away.
- Talk to Microsoft—If you absolutely cannot update by October 14, 2025, contact your Microsoft account team starting August 1 to learn about ESU fees, purchase process, and get set up for these updates.
- Act Quickly—Don’t wait. Waiting raises real risks of not getting needed security.
Positive and Negative Impact
Positive: Gives more time for organizations struggling to finish upgrades, reducing immediate worries.
Negative: It’s costly and short-term. Running unsupported versions after April 2026 puts servers in significant danger.
Key Recommendations
Upgrade soon, not later. Relying on ESU is only for safety while finishing a migration. Costs may be high, and long-term use is risky. Use this temporary period to plan and finish your migration to the new Subscription Edition.