Why is relying on a legacy System a Risk for Companies?
By Emanuel Böminghaus, Legacy Systems Expert and Managing Director, AvenDATA
By Emanuel Böminghaus
Legacy Systems Expert and
Managing Director, AvenDATA
Managing Director, AvenDATA
In many organisations today, it’s not just numerous outdated applications that remain in use but often a single, highly critical legacy system that has been running for years despite no longer supporting day-to-day operations. This system can drive disproportionately high costs, weaken IT security and create significant challenges for compliance, audits and overall operations. Businesses frequently underestimate the extent to which one legacy system can hinder their entire IT strategy.
What defines a Single Legacy System
A legacy system is software that is no longer actively used but still contains data that must be retained for legal or operational reasons. This could be a former ERP system, an old HR or payroll system, a historical finance system or even a custom-developed application. Developers have long since left the company. Frequently, after modernisation projects or carve-outs, such a system remains no longer maintained but still unable to be shut down.
Why a Single Legacy System represents a Strategic Risk
The central risk often arises because this system no longer receives updates and therefore critical security gaps remain permanently. A single legacy system can become an entry point for malware or unauthorised access, especially when old databases, outdated server systems or insecure interfaces are still active. The IT department also loses valuable time because maintaining a legacy system requires specialist knowledge that is no longer available internally. As soon as information is requested by auditing authorities, it becomes clear that no one knows how the system is operated or what data structures exist.
From an economic perspective, even a single legacy system burdens the company. The costs for servers, backup, licences, maintenance, monitoring and internal support accumulate over the years even though the system no longer provides any productive benefit. Many companies continue to pay five-figure sums annually simply because the legacy system remains in place. Added to this is compliance pressure. Data from the legacy system must remain fully and reliably accessible sometimes for decades. If no specialist knowledge is available, legal risks arise that will become apparent at the latest during an audit.
Which Information in a Legacy System is Critical
- Tax-relevant booking and transaction data
- Personnel and Payroll data from previous accounting years
- Vouchers, Documents and Attachments
- Audit Trails, Log data and System-relevant protocols
- Commercial records subject to statutory retention periods
As these data sets are often extensive and complex, they must remain accessible in some form without requiring technical know-how. This is precisely what is often no longer guaranteed in an active legacy system.
How Companies should handle a Single Legacy System
The first step is to fully analyse the legacy system and determine which data it contains, what legal obligations exist and how long the information must be retained. Based on this analysis, it can be decided whether migration is necessary or whether archiving is the most sensible solution. In practice, archiving almost always proves to be more efficient as the system can then be completely decommissioned.
After the decision, the next step is the audit-compliant extraction of the data. It must ensure that all tables, records, templates and transaction data are fully transferred. At the same time, readability, export functions and logging must be guaranteed so that even years later an auditor or insolvency administrator can verify which data was stored in the legacy system. Since staff familiar with the original application is usually no longer available after an insolvency, this step becomes even more critical.
The extracted data is then provided in an audit-compliant archiving system. This archive enables clearly defined access rights, logging, search and export options and guarantees legally compliant retention. Once these requirements are met, the legacy system can be technically decommissioned. This includes shutting down servers, removing backups, terminating licences and documenting the final closure.
Why a Single Legacy System is so Often Overlooked
In many companies, the problem arises because the system is only “running in the background” and no longer actively used. There is no responsible person, no further development and no ongoing control. As a result, the system is easily forgotten while continuing to generate costs and pose a risk.
The longer this situation persists, the greater the danger that important data will be lost, audits will fail or attackers will exploit vulnerabilities.
A Single Legacy System should never run in the Background
A single legacy system can cause significant financial, legal and security-related risks. Companies should not simply continue operating legacy systems but instead analyse them systematically, extract data in an audit-compliant manner and then fully decommission them. Only then are both compliance and IT security ensured while costs can be permanently reduced.
Planning to archive a legacy system?