Legacy systems are rarely just old code. They contain years of business decisions, workarounds, customer expectations and operational knowledge. Treating modernisation as a simple technology replacement creates unnecessary risk.
A better starting point is to map the business-critical journeys, integrations, data dependencies and failure points. This creates a shared view of what must be preserved, what can change and where the greatest value lies.
Modernisation can then proceed in controlled increments: stabilise, document, isolate, replace and optimise. Each stage should produce a visible business result—not merely a technical milestone.
The goal is not to make everything new. It is to create a maintainable, scalable platform that protects continuity while making future change easier.