Case Study
Recovering Critical Knowledge from a Legacy System Through Reverse Engineering and Modernization
The car rental company identified a key opportunity to drive innovation and tackle longstanding technical debt by addressing a persistent challenge: their legacy system had become increasingly complex, difficult to understand, and to maintain, and innovate.
The system had been developed using an outdated COBOL-to-Java conversion tool, resulting in unreadable code with zero documentation. As the customer lacked in-house expertise – even small changes were risky and time-consuming.
Rather than continuing to work around the limitations, the company saw this as a catalyst to modernize its technology stack and lay the groundwork for a more agile, scalable future.
Approach
The entire project was grounded in a structured approach developed by Grape Up consultants to thoroughly understand the existing system’s architecture and data flows – an essential step that informed every phase of the modernization initiative.
To accelerate the effort, the team introduced AI Agent Workflows – a GenAI-powered solution built by Grape Up. Leveraging this technology, experts from both companies examined the legacy codebase, extracted critical insights, and reconstructed the knowledge needed to map out the system effectively.
Throughout the process, Grape Up worked side by side with the customer specialists to deepen the collective understanding and successfully reverse-engineer the platform.
Outcome
Grape Up delivered a comprehensive understanding of the legacy system, clarifying how core operations were implemented and bridging gaps caused by years of undocumented changes and accumulated technical debt.
The customer received comprehensive and accessible business and technical documentation, which paved the way to transform the solution with greater speed, accuracy, and confidence. This included a BRD, detailed user stories, architecture, and dependency diagrams, as well as thoroughly prepared code documentation.
Beyond documentation, the client was also equipped with a precise time and budget estimate for the entire modernization effort, along with a detailed, phased modernization plan. These deliverables gave the organization full clarity on the scope, timeline, and investment required.