Modernizing the Core Without Replacing It: How Rocket Software Helps Companies Get More from RPG Applications

1. The core system is not the problem—standing still is

Across manufacturing, distribution, retail, and financial services, essential business processes still run on applications written in RPG and hosted on IBM i—the platform previously known as AS/400 and later iSeries. These systems may support orders, inventory, production schedules, accounting, and customer transactions. They have endured because they often embody decades of operational knowledge and are deeply connected to how a company works.

A proven core, however, can be difficult to adapt. Employees may face dated interfaces, teams may struggle to connect application data with newer services, and experienced RPG specialists can be hard to replace. Meanwhile, business leaders are expected to improve digital experiences, strengthen resilience, and make technology investments count.

That makes “Should we keep or replace the system?” an incomplete question. A more useful one is: How can we make the core easier to use, change, connect, and recover—while keeping essential operations running? Rocket Software offers capabilities intended to help organizations take that incremental path. The goal is not to make every legacy system permanent, but to give businesses practical options beyond a disruptive, all-at-once replacement.

2. Why RPG applications remain strategically important

RPG applications are often more than code. They can contain business rules, exceptions, integrations, and workflows developed over many years. Replacing an application may mean recreating not only its functions, but also the operational knowledge and decisions accumulated around it.

A major migration may be the right choice in some circumstances. It can also require significant investment, extensive testing, employee retraining, and careful data conversion. If a new environment does not account for the details of how the business actually operates, a transition can introduce problems even as it resolves others.

Modernization does not have to mean replacement. A company may be able to retain a reliable system of record while improving how employees interact with it or how information flows to other applications. It can also improve development practices and strengthen recovery planning. The IBM i platform continues to support organizations that depend on these established workloads.

For businesses where interruptions affect shipments, production, payments, or customer service, the ability to change carefully matters. Incremental modernization lets organizations prioritize the most pressing constraints, learn from contained projects, and avoid making one transformation responsible for every desired improvement.

3. Where Rocket Software can help

Rocket’s value is best considered across several connected needs—not as a single tool that solves every modernization challenge. Its capabilities can help organizations improve access to established applications, manage application changes, support availability and recovery, and connect core systems with other technology.

• Improve how people access applications. Many long-running RPG systems use character-based “green-screen” interfaces. Experienced users may find them efficient, but they can be harder for new employees to learn or less suited to modern workflows and devices. Rocket’s modernization capabilities can help present existing application functions through more current interfaces while retaining established business logic. That can improve usability without requiring an immediate rewrite of the underlying application.

• Bring more structure to application change. Core applications need updates as business processes, compliance obligations, and security needs evolve. Capabilities associated with Rocket’s Aldon portfolio support application lifecycle and change-management practices, helping teams track modifications and move them through development and release processes with greater discipline. A clearer, repeatable workflow can reduce reliance on informal procedures or knowledge held by only a few people.

• Support availability and recovery planning. Rocket iCluster is associated with high-availability and disaster-recovery capabilities for IBM i environments. Replication and recovery technology can form part of a continuity strategy, helping organizations prepare to restore essential services and data. The appropriate design depends on the applications, infrastructure, recovery objectives, and operating procedures involved.

• Connect established systems to newer services. A company may want information from its core applications to support reporting, partner connections, automation, or a customer-facing service. Rocket’s connectivity capabilities can help make selected data and functions accessible to other systems. For example, an organization could explore connecting order information to a digital workflow without first replacing the application that manages the order.

These capabilities address different parts of the same challenge: keeping the core useful while making the wider technology environment more adaptable. The right combination depends on the business need and the organization’s existing architecture.

4. The business case for a phased approach

Incremental modernization can make it easier to connect investment with a specific business need. If employees spend too much time navigating an interface, improve access. If releases are difficult to track, strengthen change control. If continuity depends on undocumented assumptions, review recovery arrangements. If teams manually re-enter data between systems, examine whether a controlled connection could reduce that work.

Phased work is not automatically cheaper or safer. Small projects can accumulate into a patchwork if an organization lacks standards or a long-term direction. Nor does a modern interface by itself resolve underlying security weaknesses, unclear data ownership, or undocumented business rules.

The case for a phased approach is strongest when each step has a defined purpose, accountable ownership, and measurable outcome. Possible measures include reducing the time needed to onboard users, improving the consistency of software releases, reducing manual data re-entry, or testing recovery against defined objectives. Establish a baseline before a change, then assess whether it delivered a meaningful improvement.

For technology buyers, this frames the decision around trade-offs among continuity, cost, risk, and flexibility—not simply “legacy versus modern.” It also reflects a durable enterprise need: organizations must continue to operate and adapt established systems while investing in cloud platforms, analytics, and new applications.

5. Skills, resilience, and connectivity are raising the stakes

The workforce challenge is practical for IBM i environments. When application knowledge is concentrated in a small number of specialists, routine changes and troubleshooting can become difficult to sustain. Tools cannot replace experienced people, but consistent workflows and clearer records can make work more visible and transferable. Technology investments should be paired with documentation, training, and succession planning.

Resilience is also an executive concern. Organizations need to understand which systems support critical services, how those systems depend on one another, and what recovery arrangements are in place. Regulatory requirements—including cybersecurity disclosure obligations for U.S. public companies and the EU’s Digital Operational Resilience Act for covered financial entities—underscore the importance of governing technology risk. The DORA regulation is one example of a framework focused on digital operational resilience.

Resilience is not achieved by buying a tool alone. Recovery plans need clear ownership, regular testing, and alignment with business priorities. Organizations should understand what must be restored first, how quickly it needs to be available, and whether dependencies such as data, infrastructure, and skilled staff are included in the plan.

At the same time, analytics, automation, and AI initiatives are increasing interest in information held in core applications. That interest should lead to careful choices, not indiscriminate connection. Data needs appropriate access controls, quality standards, and governance. Integration can make an established system more useful, but it also creates dependencies that need to be understood and managed.

6. A practical roadmap for modernizing an RPG environment

A credible program starts with the business, not a product catalogue. Before selecting technology, identify which applications matter most, what constraints users face, and what operational risks the organization needs to address.

A practical sequence can help teams focus their effort:

1. Map what matters. Identify RPG applications supporting essential processes, their users, important data flows, and the consequences of disruption. Include operational knowledge that may not be captured in formal documentation.
2. Choose the most important constraint. Decide whether the first priority is user access, application change, resilience, connectivity, or another concrete issue. Avoid trying to solve every problem at once.
3. Define success in measurable terms. Set a baseline and choose outcomes that matter to users and operations. Measures might include onboarding time, release consistency, recovery performance against defined objectives, or the volume of manual data re-entry.
4. Pilot and learn. Start with a contained application, workflow, or group of users. Test performance, security, and usability with the people who will operate and rely on the change. Expand only after evaluating the results.
5. Maintain a longer-term direction. Assign ownership, document dependencies, plan for skills, and periodically decide whether each application should be extended, refactored, replaced, or retired.

The roadmap should also include governance. Teams need clear decision rights, standards for integrations and releases, and a way to track whether benefits persist after a project is complete. This helps prevent a series of individually useful changes from becoming an uncoordinated environment.

7. The takeaway: modernize the business around the core

Rocket Software’s proposition is most compelling when framed as practical modernization, not effortless transformation. Its capabilities can help organizations improve access to RPG applications, bring more structure to application changes, support high-availability and recovery strategies, and connect selected core functions with other systems. Results depend on how those capabilities are selected, implemented, governed, and measured.

Rocket’s 2023 acquisition of OpenText’s Application Modernization and Connectivity business reflected continued vendor interest in helping enterprises evolve long-lived applications. For customers, a broader set of capabilities may be useful, but the important test is whether the products fit the environment, work coherently, and support outcomes the organization can measure.

The central lesson for technology leaders is straightforward: preserving a proven core does not mean accepting every limitation around it. Companies can improve the experience of using RPG systems, make application changes more manageable, and connect established processes to newer services—one well-governed step at a time.