Modernizing a manufacturing company's warranty system for the cloud

A global manufacturer of industrial equipment relied on an extended warranty (EW1) system that had served the business for decades. But as the company expanded its digital services, the mainframe platform that powered EW1 became a bottleneck—every change required weeks, and only a few experts understood its inner workings.

The company’s goal was clear: migrate EW1 to AWS so its engineers could focus on building the next-generation platform, EW2, designed for faster feature delivery and future innovation.

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The EW1 system processed critical batch jobs tied to finance, accounting, and reporting. While the Company had already modernized several components, four high-value batch jobs still depended on legacy Db2 schemas. These dependencies prevented full retirement of the mainframe and limited the company’s ability to innovate at the pace business demanded.

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The Company partnered with IT consultancy Thoughtworks and Mechanical Orchard (MO), whose modernization platform, Imogen, captures real-world system behavior and rewrites legacy code into modern, cloud-native applications.

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Together, the teams designed a low-risk, high-confidence approach:

• Observe and capture.  Imogen was deployed inside the Company’s environment to record how existing batch jobs behaved, ensuring the new versions would operate identically.
  
  
• Replicate and validate. Four remaining COBOL/JCL batch jobs were rewritten in Python running on AWS Batch, while three Db2 schemas were migrated to Postgres.
  
  
• Run in parallel.  Mainframe and cloud versions ran side-by-side until automated tests verified identical outputs.
  
  
• Cut over safely.  Batch jobs went live first while still reading and writing to Db2. Once validated, the team switched data operations to Postgres, minimizing downtime and risk.

Within four months, the four billing jobs were fully migrated and running in production. Each job moved faster than the one before, demonstrating measurable acceleration as the process matured. 

The Company achieved:

• An 80% acceleration over initial timeline estimates
• Cost reduction through decommissioning legacy mainframe components associated with the Extended Warranty workload
• Reduced operational risk through provable behavioral equivalence
• Reusable modernization patterns for future workloads
• Renewed engineering capacity to focus on new customer-facing features

Mainframe modernization doesn’t have to be a high-risk, all-at-once leap. Success comes from:

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• Proving safety first—run legacy and modern systems in parallel before cutover.
• Using real behavior as the blueprint—data-driven replication avoids re-discovery.
• Leveraging acceleration—each migration builds knowledge that speeds the next.

The Company’s experience shows how enterprises can modernize complex mainframe workloads quickly and safely—transforming legacy systems into launchpads for innovation.