London

June 28–29, 2027

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September 15–16, 2026

Berlin

November 9–10, 2026

Quantifying technical debt to modernise critical systems

A data-driven approach to exposing hidden technical debt and modernizing critical legacy systems without risky rewrites.

Speakers: Ejber Ozkan

June 02, 2026

Replacing a 20-year-old system while remaining on-air is the ultimate engineering stress test. Talk shares ITV’s framework for visualising “invisible” technical debt to justify the modernisation of critical infrastructure, moving from gut-feel to data-driven decommissioning.

LeadDev Berlin is back this November

Every engineering leader fears the “untouchable” legacy system, the 20-year-old monolith that runs the core business but blocks innovation.
At ITV, this was our linear scheduling infrastructure, a critical system underpinning our broadcast channels, yet it was effectively difficult to maintain and manage.

We couldn’t afford a high-risk “big bang” rewrite, nor could we let the debt continue to accumulate. In this session, I will share the “Technical Debt Framework” that we used to derisk this modernisation.

We moved beyond the abstract by categorising debt (Visible vs. Invisible, Positive vs. Negative Value) to secure stakeholder buy-in on a modernisation strategy.

I will cover:

  • The “Visible vs. Invisible” Matrix: How to map architectural decay against business risk to show non-technical leadership why a “working” system is actually closer to failure.
  • A Case Study: The specific engineering trade-offs of modernising an old estate, including the decision to build tactical in-house microservices versus adopting third-party tooling.
  • The “25% Rule”: The road we took to identify the operational reality of negotiating a fixed capacity for debt repayment to prevent the “spiral of reduced morale and productivity.

Key takeaways

  • A Classification Framework: A practical model for categorising debt (Architecture vs. Code vs. Infrastructure) to make “invisible” drag visible to the C-suite.
  • Modernisation Strategy: How to choose between a tactical in-house rebuild and third-party vendor adoption when replacing core legacy systems.
  • Observability for Operationalising Repayment: How to implement a standard approach that allocates up to 25% of sprint capacity to debt servicing without derailing product delivery.