According to the recent Kyndryl Modernization Report, which surveyed 2,000 business and technology leaders, the motivations vary. Many want better security, scalability, and performance. About 40% of manufacturers say they are modernizing to access advanced AI capabilities.
But modernization is harder than it sounds. The same Kyndryl report found that only about half of the companies that modernized reported better IT operations, and nearly one in five (18%) saw limited or unclear value from the effort. The report doesn’t explain why, but some of the likely reasons are covered below.
For companies running legacy systems, the risk is sharper. What happens when you replace a system you do not fully understand? What can go wrong, and what can you do about it? Here is what to know before you start.
Legacy systems rarely fail all at once. More often, the warning signs build up over time:
Migrating to modern platforms can solve these problems.
Most modernization projects begin with a blind spot. The team does not fully know how the current system is wired together, and they find out the hard way once the work is underway.
The Kyndryl report puts numbers to it. Just 5% of manufacturers say they are fully confident they know their application dependencies before they start a modernization project, and 49% are not very confident in knowing those dependencies. In other words, most companies begin with an incomplete picture of the system they are about to change.
That gap tends to show up when a system is already under pressure. Hardware may be nearing the end of its life, a software vendor may have stopped providing support, or the people who know the system best may be preparing to leave.
Replacing old technology without understanding its role in your daily operations tends to create bigger problems than the ones you set out to fix.
An old manufacturing system may quietly run core processes like equipment monitoring, production tracking, alarm handling, or connections to other applications.
Replace it without mapping the functions your business depends on, and you can disrupt operations and stall the whole project.
Many legacy systems stay in active enterprise use for 10 to 20 years, and some well-maintained core infrastructure runs far longer. Over that time, the system grows more complex as people, management, and business needs change. The knowledge of how it all fits together rarely keeps pace.
A long-time employee often knows the system inside out. They know the undocumented processes, how to fix its quirks, and the dependencies that built up over the years.
When that person retires, the knowledge leaves with them. A new hire may understand the programming language but lack the hands-on experience to keep a business-critical system running.
Systems rarely work alone. Over time, they build up dependencies across applications, databases, and functions. Change one piece, and you can derail the rest.
Some of those connections run on software bought from outside vendors, like reporting tools or custom-built add-ons. They may have been added years ago to solve a specific problem, and nobody remembers they are there.
Documentation is supposed to explain how a system was designed, changed, and maintained, with every developer’s change recorded.
In practice, the team that built the system has often moved on without leaving proper documentation behind. Operations also tend to move faster than anyone has time to document, and the people who maintain these systems are often stretched across so many tasks that documentation slips down the priority list. What is left is outdated, and it creates a gap between how you think the system works and how it actually runs.
Change a system you do not fully understand, and problems tend to arise that are expensive to fix.
The first is unexpected downtime. Alter one component that others depend on, and work stops. For industrial and manufacturing firms, halting operations means losing money in real time.
You can also lose functionality. Business rules added over the years to handle unusual cases often live only in the old code. The new system may run fine day to day, then fail the moment it hits a scenario the old code was built to catch.
There are database risks too. Migration can change how data is stored, formatted, or transferred, which leaves records incomplete or inconsistent and hard to use in the new environment.
And modernizing operational technology, like supervisory control and data acquisition (SCADA) systems, takes even more care. These systems control physical equipment in real time, so downtime or a lost alarm can become a safety risk, not just a cost.
A thorough legacy system assessment and careful system dependency mapping are what keep modernization from turning into an expensive setback. The goal is simple: understand the system as it runs today, before you change anything.
Start with how the system works right now, not how it was supposed to work years ago. Note the important tasks, when they run, what they produce, who uses the results, and what happens if they fail.
What you want is an accurate picture of today’s system, not a business presentation detached from the code or a set of diagrams that no longer match reality.
As you document the system, discover and map the connections between applications, hardware, and external systems. For SCADA and industrial environments, that means checking the alarm messaging and the input/output (I/O) connections alongside everything else that touches the system.
Databases often sit between old applications and newer monitoring tools. Map which databases exist, what they store, which applications reach them, and how data moves between them.
Record the formats, the access permissions, and the transfer schedules. These details are easy to miss in a code review, but they often reveal the connections that matter most.
Technical tools show you where the connections are. The people who run the system can tell you why those connections exist in the first place.
Talk to the administrators, operators, developers, and maintenance staff. They work with the system every day and can explain the undocumented procedures and the odd problems they have learned to handle. Then line up what they tell you against your technical findings.
Building a separate environment that mirrors your system is one of the safest ways to plan an overhaul. You can study the applications, test changes, and compare results without stopping production or putting revenue at risk.
A mirror environment surfaces the big problems early and gives your team room to work out solutions before anything touches the live system.
Break the work into stages instead of attempting one big switchover. Phased upgrades are easier to manage and let your team catch problems before they spread to other critical parts of the system.
Set clear goals, test criteria, documentation practices, and a recovery plan for each stage, in case something goes wrong.
A typical path starts with mapping dependencies and stabilizing the legacy environment. From there, emulation or virtualization can keep applications running while you prepare for migration. Moving your lower-risk applications and functions first is usually the smart way to begin.
Application dependency mapping (ADM) is the process of identifying how a system operates and how its parts rely on one another, from applications and databases to servers and external services.
Good mapping shows you what could be affected when you change any one component. That is what lets a team build a sound legacy modernization strategy and sequence the migration in the right order.
Start with the running environment. Trace the hardware, software, databases, scheduled tasks, and existing connections, then review the source code and configuration files. The people who operate and maintain the system can fill in the rest, especially the parts that were never written down.
There is no way to guarantee zero disruption, but careful planning with an expert keeps the risk low. Every system has its own architecture, its own dependencies, and its own modernization risks, so the plan has to fit the system in front of you.
When nobody fully understands a system, the worst move is to rush a full replacement. The safer path is to map what you have, document how it really runs, and modernize in stages.
That is the work Salem Automation does. Based in Winston-Salem, North Carolina, we keep mission-critical and legacy systems running, from OpenVMS and legacy system modernization to industrial automation. We meet your system where it is, not where a vendor wishes it were.
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