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Many Swiss companies still rely on business applications built more than a decade ago. While these systems remain functional within their original scope, they are becoming expensive to maintain, difficult to evolve, and unable to communicate effectively with modern APIs, mobile apps, or cloud services.
With no documentation or automated tests, these solutions depend on the institutional knowledge of a few experts and carry a technical debt that hinders competitiveness. Rather than modernizing simply because a system is old, it’s crucial to identify the real blockers: operational risks, hidden costs, or lack of agility. This article provides definitions, motivations, and approaches to transform a legacy system into a controlled innovation platform.
Understanding Your Legacy System and Why to Modernize
A system becomes legacy when it slows the business down and generates hidden costs. Its age isn’t the main factor; what matters is its impact on continuity, security, and innovation.
What Defines a Legacy System?
Software isn’t considered legacy simply because it’s old. It becomes so when its technology is obsolete, its dependencies are no longer supported, or its monolithic architecture grows fragile. The lack of automated tests and reliable documentation exacerbates this obsolescence. Likewise, an outdated user experience or ad hoc integrations confirm a business application’s legacy status.
The associated technical debt appears as a tangle of quick fixes, custom overlays, and rapid patches. Each ad hoc intervention may address an immediate need but accumulates long-term risks. As technical debt grows, maintenance costs rise, and every change becomes riskier. Eventually, the challenge shifts from purely technical to strategic.
Viewing a legacy system requires assessing its overall impact: on security with outdated component versions, on operational efficiency with degraded response times, and on the ability to integrate new services. Modernization isn’t about replacing existing systems for the sake of newness; it’s about removing blockers that limit growth.
Signs of a Blocking Legacy
A clear indicator of a problematic legacy is an explosion in maintenance costs. IT budgets get consumed by corrective operations, often without a specific budget line to reflect the reality. Behind vendor invoices lie extra delays, repetitive manual tests, and unanticipated incidents.
When adding a feature seems impossible without rewriting thousands of lines of code, you’ve hit the legacy limit. Lack of modularity and the proliferation of dependencies make every intervention expensive. Add to that the risk of key knowledge held by only a few staff members, and the system turns into a black box.
Example: A Swiss food logistics SME used a monolithic ERP from 2005. Whenever new traceability regulations emerged, teams spent weeks manually adjusting reports because there were no APIs or automated tests. This situation showed that code age wasn’t the main issue, but rather the lack of flexibility and native integration with modern tools.
Why Decide to Modernize?
Modernization aims primarily to reduce hidden costs: slow processes, data-entry errors, and manual workarounds. These inefficiencies drag on team productivity and end-user satisfaction. They often remain invisible in the IT budget but are very real in processing times and business churn.
Improving security is another major lever. Vulnerabilities accumulate when dependencies aren’t updated. An audit can reveal critical flaws exploitable by attackers, exposing the company to fines and reputational damage.
Finally, preparing for new technologies—cloud, AI, mobility—requires a modular, well-documented foundation. Modernizing is therefore not a luxury but a driver of agility and resilience to support growth and innovation.
Modernization Approaches: Choosing the Right Path
There’s no one-size-fits-all method to modernize a legacy; each path depends on context, criticality, and budget. Rehost, replatform, refactor or rebuild: the choice depends on acceptable risk levels and desired speed.
Rehost or “Lift and Shift”
Rehosting moves the application to a new infrastructure—often cloud or a virtualized environment—without changing its code. This approach is quick to deploy and removes the ERP or business solution from an aging platform. It helps address server obsolescence and benefits from more flexible hosting.
However, rehosting doesn’t tackle technical debt or architectural complexity. Overall performance and user experience remain unchanged, and application maintenance costs persist. This method should be seen as a first step toward stabilization, not a comprehensive modernization.
Example: A Swiss training organization migrated its application to a managed cloud infrastructure to replace end-of-life physical servers. While availability improved, the monolithic structure and lack of automated tests continued to hinder its evolution plans.
Replatforming
Replatforming goes a step beyond rehosting. It involves moving the application to a new platform while making targeted adjustments: migrating to a managed database, updating the runtime, or replacing middleware. Migrating to a managed database can significantly improve performance and security.
This approach keeps business logic intact, limiting regression risks. It’s suitable when functional value remains relevant but technical infrastructure and certain components need modernization. You gain operational productivity without a full rework.
The balance between quick wins and risk control often makes replatforming a key phase in a progressive modernization strategy.
Refactoring and Re-architecting
Refactoring improves the code’s internal structure without changing its behavior: removing duplication, clarifying modules, and adding unit tests. This work lays the foundation for a healthy, modular codebase.
Re-architecting goes further by rethinking the entire architecture: breaking up the monolith, introducing APIs, adopting an event bus, or progressively migrating to microservices. This transformation requires clear governance, in-depth business knowledge, and robust non-regression tests.
When done well, this approach delivers long-term modularity and innovation capacity. However, it demands high skill levels and careful team coordination.
Edana: strategic digital partner in Switzerland
We support companies and organizations in their digital transformation
Preparing and Executing a Modernization Project
A preliminary audit is essential to choose the right approach and assess risks. Testing, data migration, and AI are key components of a controlled execution.
Audit and Decision
The audit must evaluate business criticality, code quality, documentation status, and technical dependencies. This phase maps out blockers and prioritizes risks based on their production and security impact. The audit forms the foundation of a realistic, contextualized roadmap.
During analysis, deployment processes, data architecture, and user experience are also reviewed. This global view feeds the plan and determines whether lift and shift, refactoring, or a rebuild is preferable.
Example: A Swiss mid-sized medical company began its project with a comprehensive audit. It revealed a monolith without tests and undocumented business rules. Thanks to this diagnosis, the company chose a strangler fig pattern, limiting risk during the progressive migration of critical modules.
Non-Regression Testing and Data Migration
Without unit tests, every fix or change becomes a risky gamble. Implementing integration and functional tests ensures business behavior remains stable. CI/CD pipelines maintain deployment consistency and speed up iterations.
Data migration goes beyond simple copying. It requires extraction, cleansing, mapping, and validation. Historical data is often incomplete or poorly normalized. A rollback plan and a coexistence phase between old and new systems are essential to minimize downtime.
A successful strategy synchronizes versions, adjusts formats, and includes performance tests to validate post-migration scaling. Without these preparations, modernization faces costly incidents and rollbacks.
The Role and Limits of AI
AI can assist in analyzing legacy code: summarizing modules, detecting dependencies, or generating basic documentation. These capabilities accelerate repetitive tasks but cannot replace human oversight. AI cannot decide business priorities or interpret implicit rules scattered across internal procedures.
AI systems also struggle with context on large codebases. The risk of hallucinations or inappropriate fixes demands expert validation. AI should be integrated into a methodical approach, combined with user interviews and manual technical mapping.
In summary, AI is a valuable accelerator but does not replace the comprehensive audit or the business understanding required for sustainable modernization.
Adopting a Pragmatic Approach: Best Practices and the Swiss Context
Legacy modernization must be segmented, governed, and aligned with business impact. In Switzerland, SMEs and mid-sized companies favor a pragmatic approach to preserve value while reducing fragility.
Governance Best Practices
Regular technical debt reviews involve CIOs, business stakeholders, and architects to reassess priorities. This cross-functional collaboration ensures alignment between strategic goals and IT initiatives, balancing quick wins with structural work.
Implementing CI/CD pipelines alongside automated reporting on test coverage and dependency updates provides visibility into technical debt evolution. Every new feature is integrated without compromising system stability.
Moreover, a unified backlog for IT and business teams streamlines decision-making and ensures a coherent roadmap. Key performance indicators (deployment time, regression count, incident frequency) measure success at each stage.
A Pragmatic Approach for Swiss SMEs
Many Swiss SMEs and mid-sized enterprises run heavily customized ERPs for production, logistics, or billing. These systems have become strategic yet fragile. The mantra is not “replace everything” but “preserve what adds value.”
First, identify blocking processes to automate or refactor as a priority. Standardized functions can be delegated to SaaS solutions, provided they don’t undermine business differentiation. This mixed approach minimizes compromises and optimizes investment.
Finally, using open-source, modular components avoids vendor lock-in. Cloud infrastructures are sized to actual loads and monitored to ensure flexibility and efficiency in line with growing environmental, social, and governance (ESG) requirements.
Edana’s Positioning: Tailored Support
Edana’s approach emphasizes open source, modularity, and security. Our experts adapt each trajectory to the client’s context, whether a quick replatforming or a progressive refactor via the strangler fig pattern. We co-build a hybrid ecosystem combining existing components with custom development.
From the initial audit through production launch—covering data migration and AI integration—we ensure rigorous risk management. Each project targets measurable ROI, sustainable performance, and evolution capacity aligned with business strategy.
This contextual approach enables Swiss companies to transform fragile legacy systems into high-performance, secure foundations ready for future challenges.
Turn Your Legacy into an Innovation Platform
Legacy modernization is first and foremost a transformation project aligned with business goals, security, and agility. It is based on a rigorous audit, the selection of a suitable approach, and automated tests to ensure continuity. Data migration requires thorough cleansing and validation. Finally, AI can accelerate certain tasks but does not replace human expertise.
Our experts are ready to support you at every step: audit, modernization strategy, process mapping, refactoring, data migration, and cloud integration. Together, let’s maximize the value of your software assets while managing risks.
