Microsoft Rolls Out Final Six-Month Security Extension for Legacy Exchange and Skype Users

Microsoft extends support through limited security updates to help legacy Exchange and Skype users finish their migrations.

Support deadline approaching

Microsoft has confirmed that Exchange Server 2016 and 2019, along with Skype for Business 2015 and 2019, will officially reach end of support on Oct. 14, 2025.

In response to customer feedback, the company is offering a one-time, six-month Extended Security Update (ESU) program prolonging coverage through April 14, 2026.

This extension will ensure that only patches rated Critical or Important will be rolled out to legacy customers. Furthermore, Microsoft hasn’t ruled out scenarios where no new updates are released.

While this six-month ESU is designed to support entities still migrating off these legacy systems, Microsoft stresses this is a final opportunity – the April 2026 deadline will not be extended.

Enrollment is conditional and paid

Unlike regular Windows Update, ESU patches won’t be publicly visible. Organizations must manually enroll via Microsoft’s ESU platform to receive updates, as monitoring tools like Windows Update won’t be able to detect them.

Additionally, the ESU is a paid service, with pricing, licensing and implementation details available only through Microsoft’s account teams. This extension could give some breathing room to companies already in the process of migrating. However, those interested should be ready to budget and subscribe promptly.

Finding a balance between flexibility and finality

Although this move offers extra time without drastically prolonging support lifecycles, the absence of guaranteed patches means even enrolled clients might end up with no new security fixes if no qualifying vulnerabilities are found after October 2025.

Although no explicit statement has been offered, Microsoft’s stance on the issue is apparent: users shouldn’t rely on old Exchange and Skype servers for too long, as the extension will only be offered once.

Planning ahead

For a seamless transition, affected users should synchronize their migration timelines, account for added ESU costs and ensure enrollment before the October cutoff.

For guidance on retiring Skype services responsibly, users can follow our step-by-step walkthrough on how to delete your Skype account. It provides valuable information on managing changes to your associated Microsoft account.