Microsoft End of Support 2025-2026: What partners need to know

October 2025 and 2026 aren’t just calendar dates - they’re critical milestones for your customers and your business.

• Windows 10, Office 2016, and Office 2019 reach End of Support (EoS) on October 14, 2025
• Office 2021 follows on October 13, 2026

For customers, this means no more security updates or technical support. For partners, it’s a chance to guide them through a strategic modernization wave and position themselves as trusted advisors. Our experience with complex change, deep vendor relationships and robust systems ensures SoftwareOne has the staying power to navigate with you on a new journey to value.

Why End of Support matters

Many businesses don’t fully understand the implications of “end of support.” When a system reaches this stage, it doesn’t simply stop working – on the surface, everything appears to run as usual. However, beneath that familiarity lies growing exposure to serious risks.

Without ongoing updates, systems become increasingly vulnerable to security threats, leaving organizations open to attacks that could have been prevented. Compliance can also become an issue, as outdated systems may no longer meet regulatory requirements, potentially leading to legal or financial consequences. Over time, performance can degrade too, with outdated software struggling to keep pace with modern demands.

Postponing action might seem like a way to save time or resources – but in reality, it often leads to higher costs down the line, whether through emergency fixes, security breaches, or lost productivity.

At the same time, this moment presents a valuable opportunity. By transitioning to Windows 11 and Microsoft 365, businesses can modernize their IT environment and take advantage of powerful new capabilities. This includes AI productivity tools like Microsoft Copilot, cloud-managed devices that simplify operations, and advanced security features designed for today’s evolving threat landscape. What begins as a necessary change can become a strategic investment in the future.

Windows 10 – End of Support: October 14, 2025

After nearly a decade in service, Windows 10 will no longer receive security patches or technical updates.

Why it matters

• Devices remain functional but become more vulnerable to growing cyber threats without regular security updates.
• Compliance-sensitive industries risk non-compliance and regulatory breaches if systems remain unsupported.
• Over time, legacy environments may also face compatibility and integration issues with Microsoft 365 Apps, Teams, or Copilot.

The ESU (Extended Security Updates) option

For customers who need more time before upgrading to Windows 11 or a new Copilot+ PC, Microsoft has announced the Extended Security Updates (ESU) program. Through ESU, users can continue receiving critical security patches for up to one year beyond 14 October 2025.

However, partners should communicate clearly

ESU is a temporary safeguard, not a long-term solution. It offers protection while migration plans are finalized — but modernization to Windows 11 or Windows 365 remains the most secure and future-ready path.

Partner opportunity

• Position Windows 11 as the foundation for modern productivity and security.
• Help customers evaluate ESU as a short-term bridge while building migration roadmaps.
• Help customers plan migrations, assessments, and Intune-based device management.
• Introduce Windows 365 as a cloud-managed alternative.

Office 2016 & Office 2019 – End of Support: October 14, 2025

From today, legacy Office versions – Office 2016 and Office 2019 – will stop receiving security updates, bug fixes, and technical support. While the applications will continue to function, they’ll become increasingly outdated and vulnerable over time. For organizations still relying on these legacy suites, this marks an important moment to reassess their IT environment and plan for a secure, modern alternative.

Why it matters

• Risk of security vulnerabilities in Outlook, Word, Excel, and other Office apps.
• Collaboration features may degrade as Microsoft 365 evolves.
• AI and modern features like Copilot won’t be supported.

Partner opportunity

• Advocate migration to Microsoft 365 Apps, highlighting collaboration, AI, and cloud productivity.
• Offer packages combining advisory, deployment, and managed support.
• Modernize customer workflows while minimizing business disruption.

Office 2021 – End of Support: October 13, 2026

Office 2021 will reach end of support on October 13, 2026. While there’s still a year of support remaining, now is the time to start preparing for what comes next.

Why it matters

• It is the last perpetual Office release for many customers, meaning there won’t be another standalone version to move to afterward.
• Once support ends, security updates and patches will stop, leaving systems exposed to potential risks.
• Customers remaining on Office 2021 may fall behind on productivity and AI capabilities, missing out on tools that are shaping the future of work.

Partner opportunity

• Plan phased migration to Microsoft 365 to avoid last-minute disruptions.
• Position Microsoft 365 as a future-proof productivity solution.
• Bundle managed services or advisory offerings to support readiness and compliance.

Partners: The strategic enablers of change

The approaching end-of-support deadlines present a significant opportunity for partners. Many businesses underestimate the urgency of acting now, often taking the view that “if it works, why change it?” But relying on unsupported software increases security and compliance risks, while delaying modernization means missing out on the productivity and AI innovations offered through the cloud.

By engaging customers early, partners can position themselves as trusted advisors and strategic enablers of change. SoftwareOne supports this journey by providing enablement resources, advisory expertise, and service frameworks that help partners turn these end-of-support milestones into real growth opportunities.

There are three key ways partners can add value:

• Lead with insight – Explain the business impact of EOS in plain language: risk mitigation, productivity, and future-proofing.
• Unlock commercial potential – Guide customers through Microsoft licensing options and incentives.
• Enable transformation services – Wrap advisory, assessment, migration, and managed services around the transition.