.png){kind=logo}
In what industry experts are calling one of the most ambitious legacy system overhauls in recent retail IT history, North America's largest department store retailer has successfully transitioned from a 30-year-old mainframe-based Order Management System (OMS) to a modern, scalable platform — a move that has reportedly unlocked $8 billion in revenue and driven a 60% increase in digital sales.
At the center of this transformation is Arulmozhi Kasthurirengan, the senior product manager behind the new Unified Order Platform (UOP). As per internal sources, Kasthurirengan was the sole product leader driving the multi-year modernization effort that spanned more than 500 applications, 20,000+ lines of legacy code, and 45+ dependent system integrations. The project is now being cited as a benchmark for enterprise modernization within the retail IT space.
“The scale and complexity of the mainframe architecture has become a bottleneck for agility and customer experience,” said Kasthurirengan in a conversation with internal stakeholders. “We needed a system that not only supported today’s digital needs but could also scale for future innovations.”
Reportedly, the old OMS incurred high operational costs, offered limited flexibility in business configuration management, and led to inconsistent customer experiences across sales and return channels. These pain points were amplified by minimal automation and tooling capabilities.
To address these challenges, the UOP was designed with real-time order visibility and enhanced return and exchange features. The solution also streamlined the customer fulfillment process by solving systemic issues around “NIL” (Not in Location) inventory discrepancies — thereby improving order fulfillment rates across physical and digital channels.
As per the reports from the program office, the initiative resulted in the implementation of 300+ capabilities across 8000+ user stories, totalling approximately 35,000 story points. This was executed through 10 agile PODs in collaboration with business and engineering stakeholders.
Additionally, adoption of Agile-based delivery models enabled phased rollouts and reduced efforts by 30%. “This approach allowed us to move traffic from legacy systems to the UOP in a risk-averse manner — a critical factor given the business sensitivity of order processing,” noted Kasthurirengan.
Experts have also highlighted the program’s focus on automation and scalability through large-scale GCP (Google Cloud Platform) implementations, further driving down infrastructure costs while supporting high-volume demand peaks.
Coming from the expert’s table, Kasthurirengan’s strategy was anchored in four core objectives that guided the transformation initiative. His foremost goal was to build a modern and scalable Unified Order Platform (UOP) capable of supporting future business needs and technology advancements. Alongside this, he aimed to enable organizational growth by introducing new capabilities that aligned with evolving customer expectations. A key priority was also to reduce the high operational costs associated with the legacy Order Management System (OMS), and finally, to significantly improve order visibility and deliver a seamless, end-to-end customer experience across sales and return channels
“From day one, our objective was to create a solution that would not just solve our existing challenges, but also become a best practice across the retail industry,” he said. “We treated this not just as a platform shift, but as a transformation in how the business could operate.”
The transformation inescapably needs to be accredited to the GCP Checkout Migration and Mainframe Retirement projects — two critically high-stake projects that were delivered successfully under the aegis of Kasthurirengan. The projects were important due to risk mitigation in the area of retiring legacy systems, as well as maturing scalability and capability for the future.
Despite the hurdles faced—shows the experiences in some modernization journey for 45+ applications integrated in some fashion—the team executed the transition without any hindrance.“This was one of the most complex ecosystems in the retail space, and yet we delivered with precision,” Kasthurirengan added.
With no academic publications to his name, Kasthurirengan has instead let the outcomes speak for themselves — and they have reverberated across the industry. His insights now contribute to ongoing discussions around future retail trends, particularly in scalable architecture, automation, and customer-centric design.
“Retailers should look at order platforms not just as backend systems but as key enablers of customer satisfaction and business growth,” he said. “The future will demand more agility, real-time data visibility, and modularity. We’ve built the foundation — now it’s about scaling with intelligence.”
As digital commerce continues to evolve, the success of this transformation is already being regarded as a pivotal moment in retail IT — not just for what it achieved, but for the standards it set.
