Why Outdated Software Is Becoming the Most Underestimated Threat to Your IT Infrastructure—and How to Evaluate the Right Replacement.
They’re running. Most of the time, anyway. Somewhere in every company, legacy systems are quietly chugging along—often serving as the invisible backbone of critical business processes. No one touches them. No one asks how much longer this will work. And that’s exactly the problem.
In this article, we examine four key risk areas that legacy systems pose for companies—and conclude by showing what a structured evaluation of successor systems looks like, one that leads to the right decision.
1. Lost Knowledge: When No One Knows the Code Anymore
One of the most serious yet least visible risks of legacy systems is the creeping loss of knowledge. The developers who once designed the system have long since moved on to other projects, other companies—or have long since retired. What remains is code: often thousands of lines, barely commented on, poorly documented.
Legacy systems are often based on technologies that a younger generation of developers hardly learns anymore—COBOL, VB6, classic Delphi, or proprietary frameworks from the early 2000s. The knowledge resides in the minds of just two or three people. And if they’re no longer available, the company is left to fend for itself.
A simple bug fix ticket can turn into a weeks-long analysis project. An operating system update becomes a gamble—because no one knows anymore whether the application will start up again afterward.
What VIALUTIONS does: Using AI-powered analysis tools, we systematically reconstruct the business logic of existing systems—and recapture the knowledge that has been lost within the company.
2. End of Life: When the manufacturer stops—but the system doesn’t
Every piece of software has a lifecycle. End of Life (EOL) refers to the point at which a manufacturer no longer provides updates, patches, or support. Typical examples today include PHP 5.x, .NET Framework 4.5, Python 2, Windows Server 2012—or Visual Basic, which Microsoft has announced it will discontinue in 2027.
- No security patches: Known vulnerabilities remain unpatched indefinitely and are publicly listed in the CVE database—an open invitation to attackers.
- No compatibility updates: New operating system versions, browsers, or APIs are no longer supported.
- No vendor support: If problems arise, there is no longer an official point of contact.
- Rising maintenance costs: The fewer experts who are familiar with the technology, the more expensive every change becomes.
What VIALUTIONS does: We take over the operation of affected systems and work with you to manage a controlled migration—without any production downtime.
3. Strategic Dead End: When the System No Longer Fits the IT Landscape
Many legacy systems were built in a different IT world: before cloud computing, before API architectures, before the age of mobility. They run on fat clients, communicate via proprietary protocols, and cannot be integrated into modern DevOps pipelines or cloud environments.
The result: The company’s IT strategy is evolving—but the legacy system is not. New business models, digital processes, mobile access—all of these are hindered by a system designed in the 2000s. According to a 2024 Computerwoche survey, many medium-sized companies face exactly this dilemma: The system is business-critical, but strategically a dead end.
What VIALUTIONS does: We ensure the stable operation of the legacy system so your team has the capacity to build the future—and, through reverse engineering, we help you leverage the business logic as the foundation for new development.
4. Security Vulnerabilities: The Wide-Open Barn Door in Your IT Infrastructure
According to ENISA 2023, 43% of all ransomware attacks exploit known vulnerabilities in outdated software.The Verizon Data Breach Investigations Report 2026 confirms that unpatched systems are one of the fastest-growing targets for attacks.
A VDMA survey shows that, despite rising security budgets, significant gaps in maturity levels persist. While basic measures such as backups (95%) and updates (93%) are frequently cited, modern security standards are not universally established. Especially at larger midsize companies with multiple locations, established IT structures, and limited security resources, many exceptions arise in day-to-day operations: devices are deployed quickly, teams use different tools, and departments implement their own solutions. Legacy systems significantly exacerbate these vulnerabilities.
- Unpatched systems are publicly listed as vulnerable in the CVE database—attackers specifically target them.
- A lack of encryption and outdated authentication mechanisms enable unauthorized access.
- Compliance violations: NIS2, GDPR, and industry-specific standards require demonstrably secure systems.
- Production downtime caused by ransomware: In the worst-case scenario, a successful attack results in data loss, extortion, and operational downtime.
What VIALUTIONS does: We take over operations with clear SLAs, audit-ready documentation, and controlled change management—ensuring your legacy system doesn’t remain an open door to attackers.
How do I evaluate the right replacement system?
The decision to replace a legacy system is easier to make than answering the next question: With what? Choosing a successor system is one of the most strategically significant IT decisions a company can make. If the wrong choice is made, the old legacy problem turns into a new one—only more expensive and with greater pressure to deliver.
Basically, there are three approaches. Which one is the right one depends on an honest analysis of the existing system, the company’s strategy, and the market situation.
Option A: Custom Development
Custom development means the successor system is built from the ground up—exactly according to the company’s requirements. No compromises, no unnecessary features, no dependence on a standard vendor.
That sounds ideal. But it’s only ideal if the following conditions are met:
- The business process is highly unique and cannot be mapped by any off-the-shelf solution.
- The company has a genuine competitive advantage due to the uniqueness of its software logic.
- There is sufficient internal or external development capacity for implementation, testing, and long-term maintenance.
- The process is stable enough to serve as the basis for specifications for development over several years.
Option B: Off-the-shelf Software—When 80% Is Enough and 20% Needs Customization
The pragmatic approach: There is already a solution on the market that covers the majority of the required functionality. The rule of thumb is: If off-the-shelf software meets at least 80% of the requirements, the cost of customizing it for the remaining 20% is generally more cost-effective than developing a new solution from scratch.
Off-the-shelf software offers clear advantages:
- Active vendor support and regular security updates—the EOL issue is delegated to the vendor.
- Shorter implementation time compared to a custom development.
- Continuous further development by the provider, often driven by a broad customer base.
- Thanks to microservice architectures and REST APIs, modern off-the-shelf solutions can be integrated flexibly.
When Off-the-Shelf Software Fails
When customizations far exceed the 20% threshold, expensive customization projects arise that negate the advantages of the standard solution. Furthermore, the need to adapt business processes to the software rather than the other way around can create significant operational risks during implementation.
Option C: Process Replacement—Has the System Become Obsolete?
The boldest—and often the wisest—question is: Do we even still need this system in its current form? Sometimes the problem isn’t the software, but the process behind it. It was digitized 15 years ago when there was no better alternative. Today, there is.
State-of-the-art systems such as modern ERP platforms, MES solutions, or industry-specific cloud applications can handle processes that previously required custom solutions—and they do so with significantly lower operational overhead, integrated compliance features, and automatic updates.
This option makes sense when:
- The underlying business process can be standardized and no longer offers a genuine competitive advantage.
- A modern, state-of-the-art system can map the process completely and more effectively.
- The costs of operating and migrating the legacy system exceed the costs of process redesign.
- The company is willing to adapt processes to modern best practices—rather than the other way around.
Important
Option C requiresan honest assessment of your own process. If you transfer an outdated process 1:1 into a new system, you’re not solving the problem—you’re perpetuating it.
Decision Matrix: Which ApproachFits Your Situation?
How VIALUTIONS Supports the Evaluation Process
Choosing the right replacement system requires a complete understanding of the existing system—both technically and functionally. This is precisely the foundation that VIALUTIONS establishes.
Our Approach During the Evaluation Phase:
- System Takeover: We stabilize the legacy system and take the time pressure off the decision-making process.
- Reverse Engineering: We reconstruct the complete business logic—which functions are truly critical, and which have evolved over time and are dispensable?
- Requirements Analysis: Based on the business logic, we create a clear requirements profile for the successor system.
- Market Assessment: Together with you, we evaluate whether off-the-shelf solutions meet at least 80% of the requirements profile.
- Recommendation: You receive a well-founded, neutral basis for decision-making—not a product recommendation, but a strategy.
Conclusion
Legacy systems are no exception—they’re a reality in almost every company. The danger doesn’t lie in the system itself. It lies in the decision to wait another year. And then another.
And when the time comes to replace the system, the quality of the decision is crucial: custom, off-the-shelf, or process-based solution—none of these options is inherently right or wrong. The right decision is the one based on a complete understanding of the existing system.
VIALUTIONS creates precisely this foundation—and supports you from the stable operation of the legacy system through to the structured handover to the successor system.