As of today, Microsoft Teams Classic has officially ceased operations, marking the end of an era for many organizations. The decommissioning of this legacy app comes with all backend services disabled and servers shut down, serving as a pivotal moment for IT teams around the globe. This transition is not merely a routine product retirement; it signals a critical juncture that necessitates a thorough reassessment of both immediate solutions and long-term strategies, especially with the impending end of Windows 10 support set for October 2025.
Delayed Migrations, Compressed Timelines
Despite Microsoft announcing the phase-out of Teams Classic over a year ago, numerous organizations opted to delay their migrations until the last possible moment. Some relied on Extended Security Updates (ESUs), while others accelerated their hardware refresh cycles. However, these hurried rollouts often come at a significant cost, resulting in user disruptions, increased support tickets, and teams stretched thin. A reactive approach leaves little room for essential testing, documentation, or training, all while the deadline for Windows 10 looms ever closer.
Security Risks of Legacy Systems Are Escalating
The dangers associated with outdated platforms have become increasingly apparent in recent months. A study conducted by the UK’s Royal Institution of Chartered Surveyors revealed that over a quarter of UK businesses experienced cyberattacks in the past year. Alarmingly, nearly three-quarters of business leaders foresee cybersecurity disruptions within the next one to two years. This widespread concern highlights the significant risks of operating on unsupported software. With Teams Classic now entirely unsupported, any continued use exposes organizations to severe vulnerabilities, including data leaks and infrastructure weaknesses, which can tarnish brand reputation. The absence of vendor patches or official support means that any newly discovered flaws remain unaddressed, rendering systems prime targets for cybercriminals.
Windows 10 End-of-Life: The Next Major Challenge
For many IT leaders, the retirement of Teams Classic is merely the first hurdle. The end of support for Windows 10 on October 14, 2025, presents another formidable challenge. While Microsoft will continue to offer paid ESUs for additional security patches, these are costly temporary measures rather than viable long-term solutions. Relying on ESUs for an extended period can inflate costs, diminish organizational expertise as seasoned staff depart, and exacerbate vulnerabilities as unpatched systems accumulate known exploits. This situation is particularly critical for companies in regulated sectors such as healthcare, finance, or government, where compliance with security standards is imperative. Delaying migration to a supported operating system not only increases security risks but also complicates operational continuity and regulatory compliance. Although the deadlines are clear, many organizations face hurdles in migration due to budget constraints, lack of visibility into legacy dependencies, undocumented systems, and the loss of institutional knowledge from staff turnover. What should be straightforward upgrades often devolve into prolonged struggles with costly disruptions.
What IT Teams Must Do Immediately
Organizations that have not fully transitioned to the new Teams are already at a disadvantage and may be exposing themselves to unnecessary risks. It is crucial to deploy the new Teams client organization-wide, ensuring compatibility across all devices for both the new Teams client and upcoming Windows versions. Additionally, disabling Teams Classic entirely via the Teams Admin Center and enforcing “New Teams Only” mode is essential to eliminate fallback usage. Clear communication with end users is vital for managing this change effectively, which includes providing updated documentation, training sessions, and robust support channels. Most importantly, IT teams must meticulously document workflows, system dependencies, and rollback plans before key staff knowledge departs. Taking decisive action now will mitigate risk exposure and facilitate smoother technology transitions in the future.
Final Word: Act Now or Pay the Price
The shutdown of Teams Classic serves as a critical wake-up call—not just for today, but also for the approaching Windows 10 end-of-support deadline this October. IT leaders must act swiftly to guide their teams through this essential upgrade by solidifying migration plans and proactively addressing the impending retirement of Windows 10 before it escalates into an operational and security crisis. With Teams poised to unveil a series of updates in the coming weeks and months, any delays could lead to costly downtime, security breaches, and mounting technical debt.
