The rewrite was a technical success. But we missed real business opportunities and completely underestimated the effort of building a new system while maintaining the legacy one in parallel. In short, we didn&#x27;t prioritize and miscalculated big time :-)<p>The customer confidence in us had eroded because we weren&#x27;t responding to their new feature requests in the legacy system.  Plus their management didn&#x27;t want to take any risks since the new system offered to new features to them and only benefited us.