Legacy Modernization: Strangler Fig and Incremental Risk
How teams replaced ageing systems without stopping the business — microservices, containers, and phased cutovers.
Legacy modernization dominated IT backlogs in 2022. COBOL and early .NET monoliths still ran critical processes, but maintenance costs, security exposure, and shrinking skill pools pushed leaders to act — carefully.
The strangler fig pattern
Rather than big-bang rewrites, many programmes routed new functionality through modern services while legacy cores handled stable workloads. API facades wrapped old databases, giving frontends a clean contract while data migration happened in the background.
Technical targets
Containers and Kubernetes provided a consistent deploy target for refactored modules. .NET 6 migration paths helped Windows-centric estates move forward. Where appropriate, selected modules moved to managed cloud services to reduce patching burden.
People and process
Modernization failed when treated as pure technology. Training, parallel running, and clear rollback plans kept operations teams confident. Knowledge capture from senior maintainers was as valuable as the new codebase.
PrequaliQ modernizes legacy systems in phases — improving security and agility while protecting daily operations.