With just over six months remaining before Windows Server 2016 reaches end of support, now is the time to begin planning migrations for workloads hosted on this platform. Mainstream support ended on January 11, 2022, and Windows Server 2016 has since remained in extended support. However, extended support ends on January 12, 2027. After that date, Microsoft will no longer provide security updates or technical support, increasing the risk of running production workloads due to exposure to newly discovered vulnerabilities and exploits.

Active Directory Certificate Services

Many organizations are still running critical infrastructure on Windows Server 2016. Administrators often delay upgrading Microsoft Active Directory Certificate Services (AD CS) due to its complexity. However, a well-planned AD CS migration not only reduces risk but also provides an opportunity to modernize cryptography, certificate templates, and operational practices.

Certificate Authorities

Administrators must carefully migrate Certificate Authorities (CAs) running on Windows Server 2016 to minimize downtime. In environments where ongoing CA maintenance has been limited, migrating the CA database can be especially challenging. If the CA is installed on a domain controller, now is a good time to consider separating these services to ensure reliable operation. Also, it’s a good idea to evaluate the CA’s configuration and security posture during migration to enhance security and improve service resilience.

NDES Servers

Microsoft Network Device Enrollment Services (NDES) servers, commonly deployed to facilitate certificate enrollment via Microsoft Intune, pose a unique challenge during migration. Unfortunately, configuring NDES is exceedingly complex and error-prone. NDES relies on a delicate combination of specialized IIS configuration, AD service accounts, custom certificate templates, and CA permissions, making even minor changes risky without proper planning. Not surprisingly, administrators are often hesitant to touch these systems as they are notoriously difficult to troubleshoot when problems arise.

Pro Tip: We spend an entire day covering NDES configuration in the Mastering Enterprise PKI Certificates with Microsoft Intune training course. The next session is September 1-3, 2026. Register now!

Intune Certificate Connectors

Don’t overlook Windows Server 2016 servers with the Intune Certificate Connector installed. Fortunately, this is one of the more manageable workloads to migrate. All that’s required is to install new connectors on supported servers and delete the old ones.

Summary

With extended support for Windows Server 2016 ending on January 12, 2027, organizations running production workloads—especially critical infrastructure such as Active Directory Certificate Services (AD CS), Certificate Authorities (CAs), and NDES servers—face significant security risks from unpatched vulnerabilities once the OS reaches end-of-life. Careful migration planning to newer versions such as Windows Server 2022 or 2025 is essential to minimize downtime, improve security posture, and ensure long-term resilience.

Start Planning Now

Don’t leave these mission-critical infrastructure services to the last minute! Begin planning your migration today. If you’d like expert guidance, I have many years of experience migrating these workloads. I have developed specialized tools and techniques to ensure a smooth, secure, and successful transition. Fill out the form below to schedule a free one-hour consultation to assess your Windows Server 2016 AD CS workloads, identify migration risks, and outline next steps.

Additional Information

Windows Server 2016 Lifecycle Policy

PKI Fundamentals with Microsoft Active Directory Certificate Services (AD CS) Online Training Course

Mastering Enterprise PKI Certificates with Microsoft Intune Online Training Course