Legacy Application Modernization: An A-Z Guide for Enterprises

Oleh Shmidt
Yevheniia Sydorova
Daria Iaskova

Once useful, top-performing, and reliable, any software used by organizations eventually transforms into legacy, hindering business efficiency and growth. This is a reasonable consequence of the digital world spinning at an unprecedented speed.

Today more than ever before, legacy application modernization claims a significant chunk of A-list companies’ IT budgets and appears on top of the CIO’s agenda. For enterprises however, modernization is not just about efficiency—it’s about preserving an excellent brand reputation and providing users with a strong competitive advantage.

Yet, legacy modernization not only applies to architecture redesign, code refactoring or migrating a system to other platforms or services. In most cases, it involves bringing in a strategic, user-centered vision to any innovation adopted and requires developing a whole new approach to using the updated system. 

How to make the most of this tedious process? When is the right time to approach ​​legacy application modernization and how can businesses mitigate risks related to major system-level changes? We’ve collected the answers to these questions, spiced them up with a handful of practitioners’ tips on getting rid of legacy wisely, and invite you to check them out further in this article. 

What is legacy application modernization?

From the engineering perspective, legacy application modernization is a technical redesign that is needed to efficiently maintain a software system as well as enhance and scale it to meet evolving business needs. 

Depending on the specific business context, a system’s technical peculiarities, and resources available, legacy application modernization can boil down to:

  • A complete architecture redesign
  • Iterative system refactoring 
  • Component-based updates
  • Migration to alternative platforms or services 
  • A partial or complete UI redesign 
In practice, software modernization is very different for each business. Sometimes, it's just tweaking the code or updating things on the user side to make them run smoother. In other cases, the development team might have to do a big overhaul, changing up the whole tech setup, maybe even getting into containerization or microservices.

How to understand that software requires modernization?

Analyzing the variety of businesses navigating the digital age, one can reasonably be wondering: why do some companies keep on experimenting with AI and quantum computing while others are still completing migration from on-premises to the cloud? Are any of them doing wrong? Definitely not.

In essence, software modernization is a natural stage in product evolution. To be more specific, an app is usually considered outdated when it can no longer satisfy major business needs. At this stage, companies make the crucial decision: to continue supporting an outdated application and consider modernization or to deprive themselves and switch to an alternative solution.


At this point, companies often partner up with a legacy application modernization company that is in charge of carrying out an end-to-end system audit and uncovering deeper technical dependencies that determine the best possible solution for the specific business case.

Most often, the decision to update legacy systems, just like any other product-related concern, remains at a business’ discretion. In some cases, however, modernization can be a forced decision companies have no chance to postpone. These apply to any kind of regulatory changes including the introduction of new global standards and industry-specific requirements. 

Legacy boundaries put your business at risk?

Get a tailored modernization strategy

Benefits of timely legacy application modernization

Apart from hindering company-wide efficiency, legacy software holds a number of hidden risks that with time can also result in monetary losses and negatively affect a company’s image. 

On the flip side, getting software modernization done on time sets the stage for an organization's success, giving companies the freedom to unleash creativity, foster growth, and drive innovation. Let’s look at more benefits timely modernized systems can bring. 

  • Cost optimization

Timely modernization optimizes costs by eliminating the burdens of maintaining outdated systems. It introduces more efficient technologies, reducing operational expenses and freeing up resources for strategic initiatives.

  • Improved efficiency

Modernization introduces advanced technologies and methodologies, eliminating bottlenecks and enhancing overall system efficiency. This results in smoother operations and quicker response times.

  • Enhanced security

Up-to-date software is inherently more secure. Modernization addresses vulnerabilities present in legacy systems, protecting sensitive data and ensuring compliance with the latest security standards.

  • Mitigation of End of Support (EoS) risks

Staying on top of software updates and modernization mitigates the risks associated with the end of support for legacy systems. This proactive approach ensures ongoing support, security patches, and compatibility with evolving technologies.

  • Productivity boost

Modernized applications often come with streamlined workflows and enhanced features. With better tools at their disposal, employees can enhance their efficiency, resulting in a higher level of overall productivity.

  • Improved employee satisfaction

Updated software provides employees with a more intuitive and enjoyable experience. Contemporary interfaces, enhanced features, and improved performance contribute to increased satisfaction and allow employees to feel better about doing their jobs.

Challenges of enterprise software modernization

With all the benefits listed above, organizations should be willing to get started with technical system upgrades, and in fact they are. According to different sources, legacy application modernization is an ongoing or planned priority for 92% of companies. At the same time, a recent study by vFunction and Opticca revealed that 4 out 5 modernization projects fail, especially when it comes to enterprise-wide initiatives.


What is the reason for those failures?

The same report indicates that 97% of modernization enthusiasts predict someone in their organization would push back on a proposed project. 

At Trinetix, we work closely with world-renowned enterprises undergoing transformations and modernizing their systems to achieve better results and preserve a leading market position. Here is what we’ve learned from their stories: legacy modernization is as much about updating the technology side as about developing a proper adoption culture.

From on-premise to a cutting-edge global platform
A Big Four accounting firm story

Below we list common challenges of legacy application modernization enterprises usually face and share practical tips on addressing them.

Siloed organizational structures and bureaucracy 

Enterprises are complex structures where bureaucracy and decision-making gridlocks still dominate. With rounds of discussions and approvals at different operational levels needed to reach an agreement, forming a unified strategy and aligning stakeholders’ views often becomes a cornerstone to system modernization.

How can leaders deal with the problem?

Forge a close collaboration between architects and executives to prepare a hands-on implementation roadmap that aligns with the scope of the upcoming modernization project as well as takes into account the realistic tech perspective. While analyzing the current state of a legacy system, prioritize issues that require immediate attention. This will create a solid foundation for future change and stimulate more efficient and fast decision-making.

Operational biases

Organizational silos often make enterprise decision-makers disconnected from operations. Consequently, they may have limited availability of the lower-level processes and ways in which they need to be modernized. As a result, business and technical solutions implemented may lack the practitioners’ perspective and result in operational inefficiencies and budget waste.

How can leaders deal with the problem?

While preserving the balance between architects’ and executives’ points of view, remember to focus on the users of software systems, as after all, the efficiency of any tools implemented heavily relies on them. Take the time to learn their issues—initiate discovery workshops and get to know their day-to-day routines better. This approach will help to reduce operational biases and achieve better modernization outcomes.

Aim to make the most of the discovery process?
Our practitioners know how

Low change adoption culture

While keeping business objectives first, any modernization project also focuses on making the lives of their users easier. At the same time, 60% of employees report being frustrated by new software introduced in the workplace. Subsequently, such a massive pushback may become a major blocker to adopting the changes and prevent enterprises from getting the desired outcomes from their modernization efforts.

How can leaders deal with the problem?

In line with legacy application modernization, enterprises need to introduce and promote a company-wide culture of digital adoption. This will not only improve the outcomes businesses are getting from modernization but also help employers build trust and loyalty with employees by demonstrating utmost care and attention to their job satisfaction levels.

Developing digital dexterity leads to x3 productivity boost
Want to learn more?

Substantial technical debt

Every enterprise follows its unique technological journey to maturity. Consequently, when a company embarks on the path of modernization, the systems it previously utilized undergo a series of implementations and adjustments, potentially leading to increased complexity from an engineering standpoint. This creates the so-called technical debt that’s often difficult to go through.

How can leaders deal with the problem?

When dependencies among the components within an enterprise system raise concerns about the feasibility of system modernization, architects and executives may agree that building a new system from the ground up is a more viable option. In such cases, enterprises should invest additional effort in identifying potential technical risks and developing a reliable backup plan to keep the company operational during the modernization process.

Reduce enterprise software complexity
by following these 5 principles

In general, legacy application modernization solutions for enterprises are peculiar in one distinctive way: they address a more extensive scope, thereby coming with larger risks, budgets, and responsibilities. 

Below, we’ll provide some best practices of enterprise software modernization that help our clients navigate legacy challenges and get predicted results of their modernization efforts.

Best practices of enterprise software modernization

As a rule, an efficient legacy application modernization approach requires aligning the engineering and business perspectives. From our experience, however, there is a third important component: users’ perspective.

Legacy applications are usually built for hundreds of employees at once. Often, new employees literally have no choice but to use them. Despite app complexity, they manage to overcome challenges and master these apps, but the thing you never know is how much has this UX debt cost you. Considering that, enterprise software modernization should be as much about technology as experiences.

With that many aspects to be considered, a reasonable and long-awaited question is how to approach legacy modernization and get every aspect counted. Let’s have it answered.

Step 1. Evaluate the system 

As a rule, modernization is driven by specific issues that derive from the legacy application's technology, architecture, or functionality.

To make sure modernization is the only option for those issues, enterprises are recommended to analyze their systems using six objective drivers:

Business fit

Business value

System agility




Considering both business and IT viewpoints, these factors assist executives in determining whether a legacy app falls short of meeting business requirements. If the cost of ownership appears to be excessive, the technology is too intricate, or any security aspects need to be compromised, it's an indication that modernization is a must.

Step 2. Learn the UX context

Once recognizing the need for modernization, take the time to study the experiences current software systems bring, analyze the dependencies those systems have for users, and reveal any UX inconsistencies that impact the overall efficiency and satisfaction. 

  • Organize knowledge-sharing workshops, engage employees to share their feedback, review any previous changes made, and analyze if past solutions to user issues appeared useful in practice.
  • Study other applications employees are using in their day-to-day operations. This will allow for learning the patterns they are familiar and comfortable with and use this knowledge to create consistent experiences.
  • Analyze the reasons for the current UX debt. Understanding the roots will help to be future-prepared and avoid the same challenges and risks during the future redesign. 

Step 3. Evaluate modernization

When enterprises approach the technical realization of a modernization project, their next step is to choose between a variety of techniques. Depending on the ease of implementation, Gartner defines seven modernization options, which are: 

  1. Encapsulate. Leverage and extend application features by encapsulating its data and functions, making them available as services via an API.
  1. Rehost. Redeploy the application component to alternative infrastructure (physical, virtual, or cloud) without modifying its code, features, or functions.
  1. Replatform. Migrate to a new runtime platform, making minimal changes to the code, while preserving the code structure, features, and functions.
  1. Refactor. Restructure and optimize the existing code (without altering its external behavior) to eliminate technical debt and enhance nonfunctional attributes.
  1. Rearchitect. Materially alter the code to shift it to a new application architecture, taking advantage of new and improved capabilities.
  1. Rebuild. Redesign or rewrite the application component from scratch while preserving its scope and specifications.
  1. Replace. Eliminate the former application component entirely and replace it, considering new requirements and needs simultaneously.

Often, when it comes to the technical realization of the modernization project, enterprises use a mix of several approaches listed above. This allows them to tailor the strategy to the specific business needs and architecture peculiarities and achieve better results. 

Step 4. Think of the future

Another crucial step in legacy application modernization is making sure the updated solution appears useful in practice and works as intended from each of the three perspectives. 

Below are some hands-on tips on maximizing the value of modernized software systems we leverage when working with enterprise clients.

  • Make sure any adjustments are clearly and consistently documented. This will allow for efficient maintenance and agility when it comes to keeping the systems operational in the future.
  • Establish 24/7 technical support for modernized systems. This way engineers can detect technical issues at early stages and fix them before they start to affect enterprise productivity and put business outcomes at risk. 
  • Take the time to onboard employees to the changes. Establish corporate training and assign a dedicated support team responsible for answering any questions and creating comprehensive guides on using the updated systems.
  • Create and cultivate a sense of ownership among the teams using modernized systems. Let employees understand that their suggestions matter and the opinions and feelings of each team member matter. 

How to succeed with legacy application modernization?

Like any digital project, legacy application modernization requires first of all developing a thorough technical strategy tailored to specific business requirements and modernization context. At the same time, years of experience in completing modernization projects for enterprises have shown us that often the key to success is not only about making reasonable technical decisions but also about bringing consistency to the changes implemented.

This approach has already helped Fortune 500 companies maximize the value of their modernization efforts and is pending to transform your business. If you are ready to push legacy boundaries, let’s chat about making the most of your transformation efforts together.


A software system is considered legacy when it is outdated, typically characterized by obsolete technologies, architecture, or functionalities, and often poses challenges in terms of maintenance, scalability, and compatibility with modern standards.
Postponing legacy application modernization poses the risks of increased security vulnerabilities, reduced system performance, and higher maintenance costs as outdated technologies become more challenging to support and may no longer align with current business needs and industry standards.
Modernization becomes inevitable when existing systems pose security and compliance risks, especially with the introduction of new regulations like GDPR, as organizations need to align with evolving legal frameworks and ensure robust data protection measures.
Ready to explore
 tomorrow's potential?