Modernizing Legacy Systems at Scale: Gen AI-Driven Application Refactoring, Agile Delivery, and Cloud-Native Enablement Powered by GitHub Copilot

Client Overview

The client is a multinational energy corporation operating across exploration, production, refining, and marketing of petroleum. With a footprint in over 180 countries, the client ranks among the largest non-state-owned oil and gas companies globally, producing over one million barrels of crude oil daily. Beyond petroleum, the client has substantial interests in petrochemicals, coal, mineral mining, and geothermal energy. The client is deeply committed to delivering affordable, reliable, and cleaner energy to support human progress. 

The Need for Change

The client’s legacy application landscape was becoming increasingly difficult to maintain, scale, and secure. With rising infrastructure and licensing costs, limited agility, and growing technical debt, the organization needed a strategic shift toward a modern, cloud-native architecture. The lack of standardization and manual development processes slowed down innovation and impacting time-to-market. These challenges underscore the urgent need for a comprehensive modernization initiative powered by Gen AI to drive efficiency, reduce costs, and future-proof the technology ecosystem. 

Gen AI Application Modernization was required to address the limitations of the client’s legacy systems. It focused on accelerating digital transformation across legacy systems, enhancing operational efficiency and decision-making through intelligent automation. Additionally, it aimed to improve data accessibility and insight generation across complex energy workflows, while supporting the client’s sustainability goals by enabling smarter energy management and predictive maintenance. GitHub Copilot for development also played a pivotal role in this transformation by enabling AI-assisted coding, reducing manual effort, and accelerating delivery timelines.

Business Challenge

The client faced significant challenges in modernizing a vast portfolio of legacy applications. Key hurdles included:

LTM Solution

LTM deployed a 75+ member team across 5 agile pods to drive modernization using GitHub Copilot, a Gen AI-powered development accelerator. The engagement spanned over 2 years, operating under a fixed-price agile model. Gen AI Application Modernization was central to this initiative, enabling accelerated development, improved code quality, and enhanced productivity across modernization efforts.

Key offerings:

Gen AI Adoption and Benefits Realized Across SDLC

Requirement analysis and design

• Business logic extraction: Automated and accelerated requirement analysis and design using Gen AI-powered tools, reducing dependency on manual documentation and SME input.
• Architecture analysis: Enhanced architecture analysis, enabling faster understanding of legacy systems and supporting “first-time-right” design decisions.
• CI/CD pipeline design: Streamlined CI/CD pipeline design through intelligent automation and standardized templates.

Development

• Code generation (.NET & Angular): Accelerated code generation and refactoring for modern frameworks (e.g., .NET, Angular) using AI-assisted development tools.
• Performance optimization: Improved code review and standardization processes, resulting in more maintainable and consistent codebases.
• Unit test automation: Enabled automated unit test creation and improved test coverage through Gen AI-driven approaches.

Quality assurance and DevOps

• Code quality improvement: Fostered greater collaboration and innovation by embedding Gen AI into daily workflows across agile teams.

Benefits

• 15% improvement in productivity during assessment and design

Gen AI-assisted analysis and documentation accelerated the understanding of legacy systems, enabling faster and more accurate gathering of requirements and design of solutions. GitHub Copilot for development further enhanced this process by enabling AI-powered code generation, reducing manual effort, and streamlining development workflows.

• 35% reduction in lead time for business logic extraction

GitHub Copilot helped automate the reverse engineering and extraction of embedded business logic from legacy code, reducing reliance on SMEs and speeding up modernization.

• 45% faster CI/CD pipeline design cycles

Automated generation of Ansible roles and pipeline templates streamlined DevOps setup, significantly cutting down design time.

• 30% increase in code generation throughput (.NET & Angular)

AI-assisted code generation enabled developers to rapidly convert legacy code into modern frameworks, boosting delivery speed and reducing manual effort.

• 40% reduction in unit testing effort

Automated generation of unit test cases improved test coverage and reduced the time and effort required for manual test creation.

• 25% reduction in UAT defect density

Quality-optimized and standardized code, along with a shift left strategy and early defect detection, resulted in fewer issues during user acceptance testing.

• 20% reduction in bugs post-modernization

Conclusion

By integrating GitHub Copilot across the software development lifecycle, LTM enabled a seamless modernization journey for a global energy giant. The initiative not only accelerated delivery and reduced costs but also significantly improved code quality, performance, and team productivity. GitHub Copilot for development was instrumental in driving AI-assisted development, streamlining workflows, and enhancing engineering efficiency. The success of this engagement highlights the transformative potential of Gen AI in large-scale enterprise modernization.

Testimonial

“Thanks for the hard work. I wanted to share the user feedback we received yesterday. I just used the modernized App version – AMAZING!! So, fast I didn’t even realize it uploaded’”

– Business Owner - Finance Solution

“In the early days of our Modernization Program, we had growing pains, and the team also had to get acclimated to the dynamics with the different platforms’ app teams. What helped us be successful was LTIMindtree leads to being open and gracious to receiving feedback and being agile in addressing the feedback so that we could course correct.”

– AVP - Azure Operation

“LTIMindtree has built a great relationship with app owners and our team around ownership, expertise, and a primary ability to scale with more application work.”

– Lead Enterprise Architect - Application Rationalization and Modernization

“Centralized management in the LTIMindtree modernization pod has been great.”

– Program Owner - Procurements