It’s important to get customer/consumer feedback iteratively while executing modernisation. At the same time it is important to prepare/educate customer/consumer about the changes they can expect in older business processes or user experience. Customer expectations management apart from standard KPI metrics like velocity, cycle time for agile delivery can ensure smooth rollout of modernised systems.

Success while modernizing an old system using agile is about how well the modernization aligns with business goals, improves user experience, enhances system performance, and supports the team’s continuous improvement. Balancing these aspects and regularly measuring and iterating on them will indicate the true success of the agile modernization. From my experience, the focus should be both on the technical and business outcomes which includes: 1.Customer and Stakeholder Satisfaction 2.Business Value Delivered- Factors like Time to Market, Business Objectives Achieved and Return on Investment 3.Team Performance- Velocity and Sprint Success Rate. 4.Quality and Code health- Code Quality, Defects and Technical debts.

Success in modernizing an old system using Agile is measured by delivering business value, improving system quality, and maintaining customer and stakeholder satisfaction. Key indicators include timely delivery of features, reduced technical debt, system performance improvements, and user adoption. Metrics like velocity, defect rates, time-to-market, and team engagement ensure progress aligns with Agile principles. Continuous feedback, adaptability to change, and cost efficiency further highlight success, demonstrating the team’s ability to deliver meaningful, incremental improvements that meet evolving business needs.

Sprint Velocity:This measures the amount of work completed in a sprint, typically quantified in story points. It helps gauge the team's capacity and efficiency over time. Tracking this metric allows you to predict future performance and adjust planning accordingly. Customer Satisfaction:Often measured through surveys or feedback forms, customer satisfaction (CSAT) indicates how well the new system meets user expectations. High satisfaction scores suggest that the modernization efforts are resonating well with users. Cycle Time:This metric tracks the total time taken to complete a task from start to finish. A shorter cycle time indicates a more efficient process, reflecting the team's ability to deliver features or fixes quickly.

Success is measured by how quickly and smoothly new features can be delivered to customers while ensuring the system remains stable and reliable. For example, an online store switches from monthly updates to weekly updates without crashes, showing the modernization works.

When modernizing an old system using agile, I focus on a few key measures to track success. Sprint velocity helps me understand how much the team is accomplishing and whether we’re staying on track. I also prioritize customer feedback—regular input and tools like NPS make sure the updates actually meet user needs. Cycle time is another important metric, as it shows how quickly we’re completing tasks and helps improve efficiency. By combining these with open communication and regular check-ins, we ensure the modernization is delivering real value while staying aligned with user and stakeholder expectations.

Here’s how I handle it when modernizing a system with agile: I focus on three things—outcomes, feedback, and team health. Success isn’t just about delivering features; it’s about delivering value. Are users happier? Is the system faster, easier, or more reliable? I also track feedback loops—how quickly we spot issues and adapt. Finally, I keep an eye on the team. Are we motivated, collaborating, and learning? A happy, engaged team builds better software. It’s not flashy, but it works—and it’s taught me what really matters.

I would focus on ensuring happier users, fewer bugs, improved performance, and scalability. Regular feedback from stakeholders would guide my priorities, while team retrospectives would help refine our processes. Meeting sprint goals, enhancing team efficiency, and aligning with business needs would be my key metrics. I would prioritize solving real problems, improving usability, and creating a future-ready system, ensuring both technical and business objectives are met.