← Glossary
Legacy System
An existing system a business depends on that's become hard to change, poorly documented, or built on an outdated stack.
'Legacy' describes a system's condition, not just its age — a five-year-old undocumented system can be more legacy than a fifteen-year-old well-maintained one. The defining trait is that changing it safely has become genuinely difficult, usually because the people who understood it have moved on or the documentation never existed.
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