The EDI claims engine used by the customer was built on a legacy platform. It neither had the documentation nor the original development team that developed it. Therefore, every modification was a herculean task. The system was not easily configurable, had business rules hard-coded, and had deprecated/redundant code. Additionally, a large number of rules resided with its partner clearing house. The customer continued using a cross-walk provided by the clearing house due to the complexities involved in migrating the system from 4010 to 5010. The above factors resulted in unwarranted dependency on the clearing house and slow responses to regulatory and customer change requests.