The impact of continuous practices on software maintenance and evolution: an industrial case study

Abstract

Context: Continuous practices (e.g., CI/CD, observability, automated testing) are widely promoted as ways to enhance software delivery and quality. However, their impact in regulated, legacy-constrained environments remains unclear. Objective: This study investigates how continuous practices affect both delivery performance and team experience in a mission-critical system from the industry. We aim to understand both the technical outcomes and the organizational shifts that accompany the process. Method: We conducted a mixed-methods case study combining quantitative analysis of development tasks with qualitative insights from structured interviews. The analysis included time-based metrics (e.g., active working time, completion time), descriptive statistics, and hypothesis testing. Outliers were removed using an interquartile range (IQR) strategy. The interviews explored perceptions of challenges, software quality, and workflow evolution. Results: Statistical tests did not indicate significant differences in the time metrics. However, geometric trends and reduced variance suggest improvements. Interview responses further revealed that continuous practices improved the perceived software quality and process stability. Conclusions: The study offers empirical evidence on the effects of continuous practices in a real-world, legacy-constrained context. Beyond tools, success depends on how well these practices fit with existing workflows and constraints. We hope this case contributes practical lessons for teams facing similar modernization journeys.