Why Microsoft’s end-of-life deadlines demand new strategies from CIOs

On July 1st, Microsoft officially ends support for Classic Teams, the legacy version of its widely used collaboration platform. For many organisations – especially those in regulated, infrastructure-heavy industries – this deadline marks yet another test of enterprise readiness for digital transition. And it won’t be the last. On October 14th, Windows 10 also enters the final phase of its lifecycle.

These dates shouldn’t be a surprise – after all, Microsoft has long publicised its product roadmaps and support timelines. Yet, corporate readiness remains alarmingly low. In a study conducted as recently as May, only 38% of organisations reported having a defined migration strategy in place. That echoes anecdotal evidence about the experience of far too many companies: a familiar scramble before the deadline, last-minute extensions, expensive workarounds, and high-risk internal compromises.

Microsoft’s recent announcement of paid Extended Security Updates (ESUs) for Windows 10 is the latest in a pattern, providing lifelines to enterprises still stuck in transition. But they shouldn’t be considered as granting time. Instead, firms should treat them as warnings.

The familiar pattern of delay

Extended support has become a hallmark of Microsoft’s lifecycle management, from Windows XP and Windows 7 to Internet Explorer. The common denominator tends to be apathy from large organisations to have a proactive approach.

Migrations demand time, budget, and planning. They require deep knowledge of legacy systems, bespoke integrations, and application dependencies. Delays are often due to competing priorities, budget constraints, or organisations simply lacking visibility of their estate.

But as the delays add up, institutional knowledge also fades. Systems are no longer fully understood as vendors and employees disappear. And what was once a manageable migration spirals into an emergency, often requiring external intervention.

At first glance, the shift from Classic to New Teams may seem minor. Indeed, Microsoft has provided tooling and guidance for the transition. But for large organisations managing sprawling digital estates, with overlapping versions and tightly controlled change protocols, even seemingly minor changes can trigger cascading disruptions.

More importantly, the demise of Classic Teams signals a broader trend of Microsoft accelerating its withdrawal from legacy infrastructure. That means that if you’re still relying on it, you’re exposing your estate to longer-term threats.

Windows 10: The bigger storm

While Teams grabs headlines today, the real challenge is on the horizon. On October 14th, 2025, Windows 10 moves into paid extended support. On the surface, that package appears generous, with an additional three years of ESUs affording CIOs the chance to stagger migrations, reduce risk and allow for more flexible planning.

But extended support can lull organisations into a false sense of security, with the urgency diminishing. The migration is kicked further down the road. Documentation becomes stale, internal experts move on, and the eventual transition becomes riskier and more expensive than it needed to be.

The impact of delay is not just technical; it’s strategic and financial. Maintaining unsupported infrastructure diverts resources, accumulates technical debt, and introduces growing security risks. Every extension adds layers of fragility to the IT estate. 

We see this often. A transition which could have been executed smoothly becomes a last-minute emergency. Businesses are forced to call in consultants, perform emergency upgrades, or rebuild legacy applications from scratch. Often, it’s not because the migration was impossible, but because the knowledge to execute it had disappeared.

Takeaways for IT leaders

Now is the time to act and put a strategy in place. Organisations should audit their infrastructure and applications now, not in six months, and document knowledge about relevant systems before it leaves the business. Moreover, stakeholders across departments – from finance and risk, to HR and compliance – should be consulted about the migration, with broader assessments made about corporate readiness for Windows 11. Finally, realistic budgets should be set for the move, not just to prepare for acquiring new licenses but also for additional resources needed to maintain or migrate your estate or applications. 

The end of Classic Teams is more than a date – it’s an alert. Microsoft is moving on, and enterprises must do the same. If October 14 feels a way off, think again. It’s time to plan, act, and prepare. One thing is for sure: the option of running at risk with unsupported environments is simply not an option.

Jon Dedman is a director at Cloudhouse

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