Table of Contents
SCADA (Supervisory Control and Data Acquisition) systems are at the heart of many industrial installations, controlling production lines, power plants, or water distribution networks. Even in 2025, many sites continue to operate with older versions of SCADA. These systems, often installed more than ten years ago, are considered technologically obsolete but remain widely used in the industry. This persistence raises questions about the security, maintenance, and modernization of industrial infrastructures.
Migrating an old SCADA to a modern version represents a massive investment. The costs include not only acquiring new licenses but also updating hardware, training teams, and potentially interrupting operations. In some sectors like energy or chemistry, even a limited shutdown can cost several hundred thousand euros per hour, making replacement projects very difficult to plan.
As a result, many sites prefer to maintain their existing systems, even if they are more vulnerable to attacks or less efficient in some aspects.
Old SCADA systems are often closely linked to the installed hardware: programmable logic controllers (PLC), sensors, and actuators. Updating the SCADA sometimes involves replacing expensive equipment or reprogramming thousands of command lines.
Moreover, older versions are tested and proven on the existing hardware. Industrialists prefer stability and reliability over innovation, as a compatibility issue with sensors or controllers can lead to production stoppages or significant financial losses.
Operators and technicians are trained on specific SCADA systems, often for several years. Switching to a new version or another software requires comprehensive training, which represents additional time and cost for the company.
Retaining old systems allows teams to work with a mastered tool, limiting operational errors and incidents related to the misuse of a new or more complex interface.
In some industrial sectors, such as chemistry, energy, or drinking water, systems must meet specific standards and undergo regular certifications. Migrating to a newer SCADA may require new certifications and audits, significantly extending project timelines.
Industrial sites often choose to continue with validated and certified systems to comply with current standards without interrupting production.
Old SCADA systems are perceived as robust and proven. Their operation is predictable, and maintenance procedures are well-documented. Paradoxically, technological obsolescence is not always synonymous with fragility: in many cases, these systems have been operating perfectly for years without major incidents, reinforcing the idea that their replacement is not urgent.
This confidence, combined with the fear of production interruptions, hinders modernization decisions, even if more efficient solutions exist.
Old SCADA systems present vulnerabilities, especially to cyberattacks. However, industrialists implement complementary protection measures, such as network segmentation, industrial firewalls, and network supervision. These measures allow for the prolonged secure use of existing systems while gradually preparing for future migration.
According to some sectoral studies, more than 50% of industrial sites still use SCADA versions over ten years old, with adapted security measures to prevent incidents.
In many installations, old SCADA systems are connected to third-party systems, such as energy management, maintenance software, or reporting tools. Replacing a SCADA involves reconfiguring all these interconnections, a complex and costly process that can disrupt production for several weeks.
Maintaining existing systems thus allows for preserving interoperability and continuity of operations, a determining factor for decision-making in many industrial sites.