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Legacy IT Infrastructure: What It Is And How To Modernize

Unlike fine wine, legacy systems do not improve with age. While these outdated computing systems and technologies continue to support critical business operations, they often fail to meet modern performance standards, falling short in scalability, security, and efficiency. Even worse, maintenance can strain the IT budget. 

Here is a case in point: The U.S. Government Accountability Office reveals that government spending on IT is over $100 billion yearly, with a significant portion going towards maintaining legacy systems. This shows how costly it is to keep relying on outdated technology. However, this issue isn’t unique to the government; private organizations face similar challenges.

Given these drawbacks, businesses should consider modernizing their legacy infrastructure to stay competitive. This article highlights the challenges and benefits of modernizing legacy systems and provides strategies for effective modernization that align with current technological standards. Let’s begin!

Legacy IT Infrastructure: What is It?

Legacy IT infrastructure refers to outdated computer technology—systems, software, and networks—still used in organizations. Newer and more efficient alternatives are replacing these once-cutting-edge tools. It’s worth mentioning that “legacy” doesn’t always mean ancient. Due to how technology advances, even setups from just a few years back can fit this bill.

Differences Between Legacy IT Systems and Modern Applications

How can you tell which of your systems are legacy and which are modern? The table below compares the key differences between legacy IT systems and modern applications.

AspectLegacy IT SystemsModern Applications
TechnologyBuilt on older, outdated technologiesUses modern technologies such as cloud computing, microservices architecture, etc
ArchitectureMonolithic and rigidFlexible and scalable, often built using microservices architecture
IntegrationChallenging to integrate new solutionsDesigned for seamless integration with other systems
SecurityOften lack robust security measuresPrioritize security from the outset, leveraging modern security practices
AutomationReliance on manual processesEmbraces automation for enhanced efficiency
User ExperienceMay offer outdated or clunky user experiencePrioritizes user experience, often leveraging modern UI/UX design principles

Types of Legacy IT Systems

Legacy IT systems vary in type and size, like all IT systems. Let’s break down the common ones you’ll encounter in most organizations.

  • Mainframe systems. These were big players in the past, boasting large centralized computers capable of handling massive data loads. However, they’re now showing their age, and many organizations are moving towards more modern cloud and distributed computing setups.
  • Client-server systems. These systems rely on a central server for data storage and processing. While they were once the standard, they are now outdated and lack the flexibility and scalability of newer systems.
  • Old database systems. Think of outdated database technologies like MySQL 5.6 or IBM DB2 v11.1.x. They struggle with modern data modeling, scalability, and performance demands. Upgrading to cloud-based databases or NoSQL options can help overcome these limitations.
  • Old desktop applications. These are software applications installed and run on a single computer, like Windows or macOS apps. Older ones may be compatible with modern hardware or operating systems. Cloud-based or web-based alternatives offer better scalability and accessibility.
  • Old web applications. These are web apps accessible over the Internet that are behind in design, security, and responsiveness. Migrating or rewriting them using modern frameworks can improve the user experience and compliance with web standards.
  • Outdated ERP systems. Crucial for managing operations like finance and HR, old ERP systems might struggle with integration, scalability, and mobility. Upgrading to cloud-based options offers more flexibility and advanced features.
  • On-premises software. These reside on physical servers within the organization. They demand regular maintenance and upgrades, becoming costly and risky compared to cloud alternatives.

Upgrading or replacing these systems opens doors to a more modern and agile IT setup, setting the stage for growth and success.

Why Are Legacy IT Systems Still Common In Organizations?

Legacy IT systems are still widespread in many organizations for quite a few reasons, including:

  • Dependency. Many organizations rely on these old systems for vital business functions. In the UK alone, 74% of manufacturing and engineering firms depend on them for their operations. Therefore, the decision to switch cannot be taken lightly. For these companies, it can lead to workflow disruptions, data loss, and compliance issues.
  • Cost. Replacing legacy technologies can be expensive. For some organizations, it seems cheaper to maintain them in the short term, even though it might be less efficient long term.
  • Technical Challenges. These systems are deeply ingrained in an organization’s setup, making them a formidable challenge to replace or upgrade. The lack of documentation further complicates the process. But perhaps the most pressing challenge is finding skilled personnel for modernization, which 14% of respondents in a Rack space survey found tough.
  • Resistance to Change. Resistance is another stumbling block on the road to modernization. People naturally avoid change, especially when accustomed to familiar routines and procedures. Employees may push back against new technologies, fearing job insecurities or simply because they are comfortable with established methods. In the same Rackspace survey, 21% of respondents highlighted their company’s aversion to change as a major obstacle hindering progress.

Despite the urgent need for modernization to fuel digital transformation and stay competitive, these factors keep legacy IT systems in place.

Examples of Legacy IT Systems and Applications

Here are some classic examples of legacy IT systems and applications:

  • SAP. This enterprise resource planning (ERP) giant is a prime example of legacy software still prevalent today. While widely used, there’s a noticeable shift towards SAP S/4HANA for its advanced analytics and cloud capabilities. About 95% of SAP users are planning to migrate, highlighting the push for up-to-date solutions.
  • .NET and Oracle. Older versions of .NET and Oracle are also considered legacy applications. They often face issues such as performance constraints, security vulnerabilities, and compatibility gaps with newer tech. Transitioning to the latest .NET frameworks, .NET Core, or Oracle’s cloud offerings can help overcome these challenges.
  • SharePoint. SharePoint remains in use across industries, but older versions lack modern features vital for today’s businesses. Migrating to SharePoint Online unlocks superior functionalities and integrates seamlessly with Microsoft 365, enhancing security and reducing maintenance hassles. Adoption of SharePoint Online has surged by 200% over six years as organizations embrace contemporary solutions.
  • COBOL Mainframe. COBOL powers critical operations in finance and government, but there is a shortage of developers who can understand this legacy code. To address this, around 71% of organizations using COBOL are exploring modernization strategies, from cloud-based platforms to redevelopment using newer languages, ensuring scalability and easier maintenance.

These examples showcase the prevalence of legacy IT systems, but there’s a growing recognition among organizations of the need to modernize. 

Need help with legacy system modernization? ModLogix can help you on your journey towards contemporary solutions. Get in touch.

Risks of Operating Legacy IT Systems

Is sticking with your legacy system tempting? While it may seem functional now, here’s why you should rethink that.

  1. Security Risks. Legacy systems typically lack the most recent security features and upgrades. They are more vulnerable to cyber-attacks, breaches, and data leaks.
  1. Compatibility Issues. As technology evolves, many legacy systems may struggle to integrate or communicate effectively with newer software. This can result in operational inefficiencies and limited functionality.
  1. Performance Limitations. Outdated technology and software may fail to satisfy the performance requirements of today’s business climate. This means slower procedures, downtime, and poorer production.
  1. Cost of Maintenance. Maintaining and supporting legacy systems can be costly. It requires specialized expertise to work with, and frequent repairs or patches.
  1. Regulatory Compliance Challenges. Outdated systems don’t meet the latest regulatory standards. It raises the possibility of fines for non-compliance, legal problems, and damage to reputation.
  1. Lack of Support. Vendors may discontinue support for older systems. Organizations will be left without access to essential updates, patches, or technical assistance.

Best Practices For Migrating Legacy IT Infrastructure

So, how do you get started with legacy system modernization? The following best practice steps can help.

Craft a Project Plan

Start by outlining your objectives, milestones, and tasks, along with a timeline and resource allocation. This is the most important part of the project. Get this right, and you’ll likely get other aspects right.

Identify Dependencies

Document all connections between systems, applications, and data, both source and target, to plan the migration sequence and minimize disruptions.

Stay Agile

Flexibility is key. Be ready to adjust the plan as needed to tackle unexpected challenges swiftly. Leveraging agile methodology will help.

Test Thoroughly

Regular testing, covering both functionality and performance, is essential to catch any issues early on.

Ensure Data Integrity

Data accuracy and integrity are paramount. Cleanse, validate, and back up data to prevent any mishaps.

Verify Security 

Double-check security measures, including access controls and encryption, to safeguard sensitive data.

Document Everything

Keep detailed records of plans, dependencies, tests, and any adjustments for ongoing maintenance.

Migrate Gradually

Rather than a sudden switch, opt for a phased migration to spot and solve issues progressively.

By following these steps, you can streamline the modernization process and ensure a smooth transition to updated systems.

Common Mistakes in Migrating Legacy IT Infrastructure

Avoiding mistakes when migrating legacy software systems can save significant time, money, and frustration. Here are key pitfalls to watch out for:

  1. Lack of Planning. Without a detailed project plan, a lot of things can go wrong, resulting in a botched migration. Careful planning, where all stakeholders are involved, is essential for success.
  1. Ignoring Dependencies. Legacy systems are often deeply integrated and complex. Not identifying and documenting dependencies between systems, applications, and data can cause major disruptions and errors.
  1. Insufficient Testing. Poor testing can leave critical issues undetected until after the migration. Comprehensive testing is crucial to ensure the new system operates smoothly.
  1. Neglecting Data Quality. Overlooking data cleansing and validation can result in inaccurate, corrupted, or lost data, compromising the new system’s integrity.
  1. Weak Security Measures. Failing to prioritize security during the migration can expose sensitive data to breaches. Robust security assessments and encryption practices are essential.
  1. Skipping Documentation. Failing to document the migration process, changes made, and lessons learned can hinder future maintenance and upgrades. Proper documentation is critical for ongoing success.
  1. Rushing the Migration. Attempting to migrate everything at once can overwhelm the system and the team. A gradual approach helps identify and resolve issues incrementally.

Benefits of Migrating Legacy IT Infrastructure

Updating legacy systems significantly impacts businesses positively. Here are some of the benefits to expect.

Improved Efficiency

Upgrading your IT infrastructure delivers faster, streamlined, and automated systems. This new infrastructure means improved efficiency and better overall productivity.

Adaptability and Scalability

Due to their flexibility and scalability, modern IT systems may easily adapt to changing business demands without causing significant interruptions, supporting growth or contraction as needed.

Enhanced Cybersecurity

Modern systems offer advanced security features, regular updates, and threat detection, reducing the risk of cyberattacks and protecting sensitive data.

Lower Maintenance Costs

Newer systems reduce maintenance costs due to fewer compatibility issues, less need for specialized skills, and better vendor support and warranties.

Improved User Experience

Modern IT solutions provide intuitive interfaces and better accessibility. This increases user satisfaction, reduces training time, and enhances productivity.

Supports Evolving Business Needs

Modern infrastructure allows businesses to adapt quickly to market changes, integrate new technologies, and effectively meet compliance requirements, keeping IT aligned with business goals.

Boosts Enterprise Value

Investing in newer IT infrastructure demonstrates a company’s dedication to innovation, increasing corporate value and drawing in additional partners, investors, and clients.

How Can One Best Migrate Legacy IT Infrastructure In Small Organizations?

When migrating legacy infrastructure in small organizations, ensuring a smooth transition and minimizing business disruption is important. Here are some recommended strategies:

  1. Cloud-based Solutions. For small organizations seeking cost-effectiveness, scalability, and flexibility, cloud solutions are the best option. Systems and applications that are moved to the cloud are more robust, operate more efficiently, and cut down on hardware costs.
  1. Software-as-a-Service (SaaS). SaaS offers a practical alternative by hosting applications online. This eliminates the need for hardware, software licenses, and infrastructure management, providing cost savings for small businesses. SaaS providers handle updates and security, allowing organizations to focus on core activities.
  1. Open-source Software. Open-source software is another cost-effective legacy migration option. It offers small businesses free, customizable solutions, avoiding proprietary software costs. The robust support community can assist during the migration process.
  1. Combining New and Existing Systems. Small businesses can also combine legacy systems with new technologies, allowing for a gradual migration. This approach minimizes disruption by selectively migrating certain systems while retaining essential functionalities.
  1. Custom Software. In some cases, the solution is to build a new application from the ground up using cutting-edge tech. Working with experienced software developers, small organizations can create scalable and seamlessly integrated systems that fit their specific requirements.

Case Studies of Successful Modernizations

At ModLogix, we have helped organizations across industries in their digital transformation efforts. Here is one example.

Migrating ASP.NET Webforms to Microsoft Azure

Our client, a healthcare organization, manages a secure and scalable database for sensitive healthcare data. Their web application uses biometrics for user authorization and record tracking.


  • System Environment. The legacy system was hardware-specific, posing risks during cloud migration.
  • Database Compatibility. Upgrades were needed to align the MS SQL database with Azure SQL.
  • Firewall Issues. Azure Firewall was incompatible, requiring a switch to Cloudflare Firewall.


  1. Development Environment. We set up a cloud-based environment to test and identify issues without affecting production.
  2. Refactoring and Configuration. We modified the biometric service and system for optimal performance on Azure.
  3. Performance Optimization. We rewrote the report generation feature, making it 200 times faster.

The result was a secure solution with a 99.99% business continuity rate and significantly faster report generation.

We have done dozens of similar projects here at ModLogix. Visit our case studies page to see more.

How ModLogix Can Help Modernize Your Legacy IT System

Updating legacy IT infrastructure is one way to remain competitive in today’s dynamic business climate. However, the key to making the most of your legacy transformation is working with a top-notch modernization company like ModLogix, which has years of experience handling legacy system upgrades, including on-premises cloud migration using a stack of modern technologies.

Our migration experts will audit your existing legacy systems, create a customized legacy modernization plan to minimize disruptions and guide you smoothly through the transition. We keep you informed at every step, resulting in a state-of-the-art system that boosts efficiency and revolutionizes your operations.

Contact us today to get started.

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