Hardly any system is a complete green-field creation. Typically, existing systems must be expanded, replaced, or new pieces must be integrated with an existing ecosystem and infrastructure. Most often, the legacy system’s documentation is dated, basic assumptions are not spelled out, there is no comprehensive security design, side effects are folklore, and the semantics of interfaces is inconsistent at best. We help you to understand your legacy systems, as a sound basis for decisions on future development or replacement. To this end, we discover, analyze and document the structure of your legacy system both technically and from a domain perspective. To avoid costly mistakes altering the existing system, we try to understand the original design decisions, the “why?”.