# Legacy modernisation · Glossary
Updating or replacing ageing software and infrastructure so that it is secure, maintainable and able to support new requirements, such as integration, analytics and AI.
[Glossary](/glossary) · Platform and software engineering

# Legacy modernisation

     Updating or replacing ageing software and infrastructure so that it is secure, maintainable and able to support new requirements, such as integration, analytics and AI. Approaches range from rehosting and refactoring to incremental replacement.

## Why it matters

     Legacy systems often hold critical data and business rules but are hard to change, integrate or secure. They can block analytics and AI initiatives because data is difficult to extract and processes are hard to automate.

     Incremental approaches, which replace functions one at a time behind stable interfaces, usually carry less risk than large one-off replacements and deliver value earlier.

## In practice

     For example, a UK membership body running on an ageing bespoke system might first expose member and payment data through APIs, then move renewals into a new service, leaving other functions on the old system until they can be replaced safely.

## Where Rodan fits

     Rodan modernises systems incrementally through [Digital Products and Platforms](https://rodan.io/what-we-build/digital-products-platforms) and [Platform and Cloud Engineering](https://rodan.io/platform-cloud-engineering).

## Related terms

- [API (application programming interface)](/glossary/api)

- [Infrastructure as code (IaC)](/glossary/infrastructure-as-code)

- [Data architecture](/glossary/data-architecture)

- [Robotic process automation (RPA)](/glossary/robotic-process-automation)
HTML: https://rodan.io/glossary/legacy-modernisation