Calor Gas, one of the UK’s most trusted energy providers, has supported off-grid homes and businesses for over 85 years. As part of its digital modernization initiative, Calor sought to transition critical legacy applications—developed in-house over the course of decades—to a secure, manageable, and modern desktop environment. These applications, although business-critical, were incompatible with current operating systems and lacked traditional installation media and documentation.
Operating on Windows Server 2008 and Citrix XenApp 6.5, Calor’s legacy IT environment posed increasing risks in terms of security, compliance, and operational sustainability. Microsoft’s end-of-support timelines and the high cost of extended security updates added urgency to the migration effort. Many legacy applications were incompatible with Windows 10 or Server 2019 and could not be easily redeveloped without significant time and financial investment.
A modern desktop strategy required full compatibility with Citrix Cloud infrastructure and native operation across Windows 10 and Server 2019 environments, while preserving performance and application integrity.
After evaluating various options, Calor partnered with appCURE to leverage its Studio product’s unique “running capture” technology. This approach enabled the IT team to capture and transform live, running applications—without relying on install media or vendor intervention—into Microsoft-standard deployment packages.
These packages were then tested and deployed on Citrix Cloud, where they demonstrated improved performance compared to their original hosting environment. This seamless transition eliminated the need for costly redevelopment and allowed Calor to unify their OS estate, reducing complexity and lowering the management burden.
⚙️ Technical Highlight: appCURE Studio enables real-time capture and transformation of running applications for rapid deployment across cloud, virtual, and physical environments.
Legacy applications now run natively on modern Citrix Cloud infrastructure. Not only do they perform better than before, but the migration also improved manageability, sustainability, and security posture.
The retirement of Windows Server 2008 reduced dependency on unsupported platforms, eliminated the need for costly support contracts, and aligned with Calor’s green IT goals by cutting down server use and resource overhead.
🔒 Security & Compliance Impact: Migration to modern supported platforms dramatically reduced exposure to unpatched vulnerabilities and compliance risks associated with outdated infrastructure.
To go from applications that could not be installed on modern systems to working seamlessly—and faster—was incredible to see.
Calor Gas has outlined a clear strategic roadmap to build on the success of their modernization efforts, focusing on automation, scalability, and future-ready application delivery.
| Strategic Focus Area | Planned Actions |
|---|---|
| Application Lifecycle Automation | Windows Integrate automation capabilities with appCURE10, Windows 11 |
| Business Unit Expansion | Extend application transformation to other business units |
| Monitoring & Support | Improve monitoring and support for legacy-modernized applications |
| Future Delivery Models | Align with cloud-native application delivery strategies |
appCURE has played a critical role in delivering expert-led services that accelerated Calor Gas’s platform transition:
Comprehensive legacy application assessment and validation across environments
Seamless application capture, packaging, and remediation using appCURE Studio
Thorough deployment testing within the new Citrix Cloud infrastructure
Continued post-migration optimization and support, ensuring long-term application stability and performance
appCURE has been an indispensable partner in our transformation program. Without them, this project would not have been viable from a time or cost perspective.
Calor Gas successfully executed a complex legacy application modernization program using appCURE Studio, enabling its transition to a modern, secure, and agile IT environment without sacrificing performance or undergoing extensive redevelopment. The project exemplifies how innovative application transformation platforms like appCURE can accelerate digital transformation initiatives, reduce cost, and improve compliance at scale.
