The installation of the components and of the software modules in refit projects is designed similarly to that of new vehicles. The difference is that in refit projects, existing hardware and software must be integrated and docked onto the new system by interface. These interfaces can be programmed by our developers, which guarantees a clean migration with the legacy system. Backward compatibility is an important subject in this context. The FELA team has proficient experts available for the integration of existing hardware and software who, by means of reverse engineering, can connect our product systems to the existing equipment of the customer. There is also a need to plan, with the customer, the transition period in mixed operation and anticipate possible problems (in hardware and software) and to solve these.