Many applications that run businesses today are valuable, long-lived systems full of domain knowledge, customer workflows, and hard-won architectural decisions. Modernising them is not about replacing everything. It is about making them easier to understand, safer to change, and ready for future requirements while they remain in operation.

AI can support this work by helping teams explore unfamiliar code, identify dependencies, draft characterization tests, document behaviour, and prepare refactorings or migrations. But successful modernisation still depends on clear architectural intent, reliable feedback, and disciplined engineering practice.

This talk presents a practical modernisation playbook for teams. We will look at how to analyse existing systems, protect business-critical behaviour with tests, use static and dependency analysis, introduce changes in small reversible steps, and enforce architectural boundaries through CI.

Attendees will leave with a concrete model for using AI as an accelerator in legacy modernisation, improving delivery capability, reducing risk, and creating systems that are more adaptable, maintainable, and future-ready.