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The Top Risks of Running Legacy Software

By: David Mastrella
Published: Wednesday, 01 March 2023

The Dangers of Legacy Software 

Any business that has been around for longer than a decade probably has legacy software. Sales systems, customer service applications, and legacy infrastructure are just a few applications common in long-term businesses. Most business leaders are at least somewhat aware that the systems running their business should be modernized, however, they choose to put it off year after year. It's understandable. After all, they think, it's been working this long and the staff already knows how to work around any glitches or inefficiencies there may be. We'll set aside budget to upgrade next year.

While it's possible this may be the right decision for a few (under certain circumstances), however, more often than not it ends up costing an organization much more in the long run. The reality is, with these systems come issues with management, upgrades, support, security, and the added cost of running the application. Most of all, it leaves risks of a data breach from legacy application security vulnerabilities.

Oftentimes, the issue for organizations is that the staff using the software don't want to change it. Even when they do, administrators might discuss it with stakeholders, but usually, the answer is the same - it works, so they don't want to "fix" it. These stakeholders might feel differently, however, if they were aware of the many dangers and costs associated with legacy software. Let's review the biggest pitfalls you could face when prolonging the use of legacy software within your organization.

Security Vulnerabilities

The biggest issue of all is the security of a legacy system. Vulnerabilities are bound to creep up on the system, especially if developers no longer support the application and refuse to deploy any security patches. Legacy systems are usually built with some kind of security integrated, but the security rules do not defend against the latest threats. 

Outdated software is one of the most common cybersecurity threats to a business, and this includes applications closed off to the public internet. Insider threats - both intentional and unintentional - can affect internal legacy systems. For example, an employee could unintentionally run malware or ransomware, and legacy software does not have the security rules in place to stop a revenue-impacting payload.

Older Infrastructure Required to Support Software

Legacy software often needs infrastructure that supports it. For example, most legacy software can't run on newer operating systems. Outdated operating systems have the same security issues as outdated third-party software. Once the operating system developer no longer supports the application, developers no longer deploy security patches to stop the latest threats from exploiting known issues. This presents a real problem for administrators running outdated operating systems on critical network servers.

Leaving older infrastructure active on the corporate network environment adds even more vulnerabilities open to threats. Administrators might test the legacy application on newer infrastructure, but usually, testing presents bugs that cannot be remediated. The problem leaves administrators stuck with old vulnerable infrastructure that takes additional overhead to maintain.

Limited User Features

Older software is built for users familiar with features from a decade ago. Users of today expect specific features in their productivity software, especially when they use the software to perform their day-to-day job functions. Because developers for legacy applications no longer support them, developers won't add features in future releases. Applications with limited functionality affect productivity and, ultimately, your revenue.

Incompatibility with Newer Software

To attract users, developers often create their software to integrate easily with other applications. Take Microsoft Office 365 as an example. One reason it's so popular in enterprise environments is its compatibility with a wide range of other applications. Application developers also build their software to support other popular applications, including Office 365.  Compatibility makes it easier for administrators to support an application, which saves time and money.

Legacy software often runs in a siloed environment where users work with it for a specific job function, but they cannot use it for any other activities. This inefficiency frustrates users, and it means they need to have a legacy application open for a single job function when newer applications integrate better and have features users prefer. The legacy application becomes a bottleneck in daily operations.

No Developer Support

No matter how smoothly software runs, eventually, administrators run across a bug. Finding the root cause of the bug might be more difficult than expected, but a good developer should support customers in finding remediation for the issue. Software developers offer a wide range of support, including deployments of patches and updates, phone support, and communities dedicated to discussing common issues and fixes.

After developers release several new versions, they retire support for much older versions. Legacy applications often have no support except in some expensive circumstances where businesses pay for extended support. Unless you have a contract forcing developers to continue support on legacy systems, developers eventually stop their support of your issues.

Without support, administrators are forced to find inefficient workarounds, which frustrate end users and anyone forced to support the system. This pitfall creates a domino effect where administrators cannot replace older infrastructure and causes even more bugs in the environment. Workarounds add inefficiencies to user productivity, which costs corporations money in downtime and employee performance.

Non-Compliance Violations

Several strict compliance regulations require corporations to do everything necessary to protect data or face hefty fines for violations. Fines for General Data Protection Regulation (GDPR) and the subsequent California Consumer Privacy Act (CCPA) can cost corporations millions if they are found to be in violation of standard protocols. CCPA and GDPR are just a couple of compliance regulations targeting industries that store consumer data.

Outdated software violates compliance regulations requiring corporations to do everything necessary to protect data. Leaving legacy systems operational allows security vulnerabilities to persist, and administrators don't have the ability to patch unsupported software to remediate any cybersecurity issues.

Forgotten Legacy Applications

Any corporation that doesn't audit the environment could mistakenly leave legacy applications available to users. It's not uncommon for administrators to be unaware of legacy applications on the network environment. Data stored in these applications won't be included in backup strategies, failover infrastructure, and recovery routines.

In this scenario, only a few users request access to the application, but keeping a legacy application unnecessarily increases the risks of a cybersecurity incident for few benefits. Users should be migrated to the official corporate application, and the legacy application should be retired.


Every one of these dangers leads to a potential cybersecurity incident. Without a supported application, you can no longer keep your infrastructure up-to-date and patch software with the latest security updates. With older outdated infrastructure, you add even more risks to the environment with its own vulnerabilities.

When software is no longer supported by its development team, it's time to migrate to a supported application. The application can be customized to have the features necessary for user productivity, and administrators can upgrade infrastructure to the latest technology. Your organization avoids compliance issues, and your users become more productive, giving you a better return on your investment.

Many clients come to us looking to add features to their legacy code. Depending on what they currently have in place, it may be possible to address some shorter-term goals working with the software they currently have. If the code is very outdated or was not architected efficiently from the start, there may, however, be little we can do with the existing code. A thorough code review is typically the recommended approach. It's a reasonably priced way to assess the condition of your current software, possible ways to address some immediate needs, and a roadmap to get you where you'd like to be in accordance with your budget.


Tagged as: Legacy Software, Custom Software, Custom Development, Code Reviews

David Mastrella

About the Author:

David Mastrella

As co-owner of custom software development company, Envative, David has been immersed in Internet based application design & development for the past 30 years – with total development experience exceeding 30 years. He has held positions ranging from senior developer, systems manager, IT manager and technical consultant for a range of businesses across the country.  David’s strength comes from a deep knowledge of technologies, design, project management skills and his aptitude for applying logical solutions to complex issues.