Understanding an application?s functional and non-functional requirements is normally seen as essential for developing a robust product suited to client needs. This paper describes our experiences in a project that, by necessity, commenced well before concrete client requirements could be known. After a first version of the application was successfully released, emerging requirements forced an evolution of the application architecture. The key reasons for this are explained, along with the architectural strategies and software engineering practices that were adopted. The resulting application architecture is highly flexible, modifiable and scalable, and therefore should provide a solid foundation for the duration of the application?s lifetime.