What is Legacy System? — UK Software Development Guide
Direct Answer
A legacy system is any software, hardware, or technology that continues to be used despite being outdated or superseded by newer technologies. In software development, a legacy system is typically characterised by: difficulty making changes safely, outdated programming languages or frameworks, lack of automated tests, poor documentation, and accumulated technical debt that makes modernisation challenging.
Legacy-system in the UK
UK businesses have significant legacy system exposure — particularly in financial services (legacy COBOL mainframes), the public sector (ageing government systems), and manufacturing (on-premise ERP systems). UK GDPR creates specific urgency around legacy systems: systems that cannot implement encryption, data subject rights (erasure, portability), or audit logging may create ICO compliance risk. Cyber Essentials also creates urgency: legacy systems that cannot be patched accumulate security vulnerabilities, failing the patch management control. ClickMasters specialises in UK legacy modernisation — with particular experience in COBOL-to-cloud migrations and UK GDPR remediation of legacy systems.
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