In years past, I have replaced old AS-400, windows applications, telecommunication platforms, consolidated old apps into web and mobile applications using relatively small teams of talented professionals. My transitions away from legacy systems have taken months, rather than years, by using scrum and agile methodologies and small, focused teams. I typically use shadowing of the business processes to gather requirements rather than spending weeks in long, drawn out meetings. All deployments have ended in high customer satisfaction and much more control over the overall business process as requested by upper management. Hoping to do the same here in Russia!