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8 Legacy System Modernization Approaches to Save Your Enterprise Software

Modern technology moves so fast that even well-made software becomes legacy after several years on the market. And without new functionalities, tools, and technologies, it’s challenging to compete and attract new users. By constantly maintaining and updating your software, you can keep it competitive and ensure a positive user experience.

One way to keep your enterprise systems working efficiently is with smartly planned and professionally executed modernization. This comprehensive article covers the key benefits you can expect from updating your legacy system. You’ll also find detailed descriptions of eight popular modernization approaches along with tips and tricks.

This article will be helpful for project leaders planning to update their legacy software and looking for experienced development teams.

The impact of legacy systems on your business

What is a legacy system?

According to Gartner, a legacy application or system is based on outdated technologies (often defined as a system over a decade old) but is critical for day-to-day operations.

Legacy doesn’t always mean old. Even a system that’s just a couple of years old can be called a legacy system if it implements poor architectural decisions, uses the wrong technology, lacks scalability, etc.

You can call an IT solution legacy when it:

  • Hampers further software development
  • Doesn’t allow for easy implementation of new features
  • Restricts third-party integrations with newer software and modern third-party tools
  • Slows down day-to-day operations
  • Is hard to maintain, support, and scale

How can a legacy system hold your business back?

Long-term use of legacy software can bring various negative consequences to your business. Here are a few examples of common burdens you have to deal with when managing legacy software:

burdens of managing legacy software

Significant consumption of IT resources. Organizations must support and update their critical systems to keep the business running. The problem is that maintaining legacy software requires much more time and effort than supporting systems with a modern architecture. For instance, each time you want to add a new feature or integrate a third-party tool to a legacy system, your developers need to check compatibility first. They also need to spend time coming up with non-trivial solutions in case your software doesn’t support certain new technologies.

Slowing down of business processes. Besides consuming your engineers’ time, lack of support for new technologies and compatibility issues affect business processes. Say your tech department manages to make new and old software work together. Such customized solutions usually make code bulky and hard to maintain. This often leads to errors in your software, which, in turn, slows down business processes, as users can’t operate the product as expected.

Increasing expenses for legacy system maintenance. When putting out fires caused by issues we mentioned earlier, you might spend lots of funds supporting legacy solutions. Thus, you will have less money to invest in your product’s evolution and business growth. Sustaining business operations can occupy up to 55% of an organization’s entire IT budget. The most tragic thing about this situation is that each year, a system will require more and more resources for maintenance.To better understand the scale of the problem, let’s take a look at real numbers. In the US, 10 critical legacy IT systems used by the federal government (ranging from about eight to 51 years old) collectively cost about $337 million annually to operate and maintain according to a 2023 publication from the United States Government Accountability Office [PDF].

Who should care about legacy systems?

The way to avoid the burdens of maintaining legacy software is to modernize it. Let’s explore several cases when legacy system modernization is especially important:

  • Your organization uses a custom enterprise system for day-to-day operations, and regular updates and improvements are vital. In this case, your employees will require modern third-party solutions to integrate with the existing system and keep up with evolving business needs and trends.
  • You develop an IT product for businesses and want to make sure your customers are satisfied with the system and willing to make a long-term commitment to it. One way to ensure this is by providing capabilities to integrate popular third-party solutions in your software. The 2023 Cloud Modernization Research Report claims that 43% of IT professionals admit to being concerned about compatibility issues with legacy systems.
  • You provide a third-party tool that can be integrated into other software, and it’s crucial to keep it compatible with modern architectures and solutions. According to Deloitte, over 60% of businesses struggle with integrating legacy tools into their new applications.

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Why modernize your legacy system: 6 business benefits

Updating a legacy system requires experienced and skilled software developers, thorough planning, expendable resources, and significant investments. Thus, you need to analyze the pros and cons of modernizing your system prior to diving in.

Before exploring the details of how to modernize outdated systems, let’s discuss what business advantages you can expect as a result.

benefits of modernizing legacy systems

1. Competitive advantage. Software providers who offer modern and flexible products are more likely to win over customers. Even if your main competitors also offer legacy systems, you never know when they plan to upgrade them. The sooner you start planning system improvements, the more opportunity you have to get ahead of competitors.

2. Expanded target audience. The main long-term benefit of making your systems flexible and compatible with new technologies is an improved user experience. Great service will make current customers stay with your company. Support for different platforms along with the ability to integrate with third-party services can help your product reach an even wider audience.

3. Enhanced security. Legacy systems are especially vulnerable to attacks, as they usually have more bugs and vulnerabilities than new solutions because of continuous increases in the amount of code. Even if you have third-party cybersecurity products integrated into your system for additional security, updating them isn’t enough. Although developers of security solutions regularly release patches to fix discovered vulnerabilities, legacy systems often can’t keep up with new software versions. Modernizing your software is the most efficient way to protect business and user data, as it will allow your product to support the latest cybersecurity requirements.

4. Reduced expenses. At the beginning of the legacy system modernization journey, you’ll likely invest significant resources into new technologies and systems. However, supporting them will be much cheaper in the long run, unlike supporting your legacy system, which will become more and more expensive each year. Also, using modern technologies unlocks new possibilities like optimizing business processes that could lead to revenue growth.

5. Regulatory compliance. The ability to update your systems also makes it easier to ensure compliance with laws, regulations, and other security requirements. Not adhering to relevant requirements that apply to your software type and industry (HIPAA, PCI DSS, GDPR, etc.) may cost your business significantly.

6. Business growth. Enhancing your systems with cutting-edge technologies like AI and ML, the blockchain, and big data can also bring some additional perks. By leveraging the latest technology trends, you can significantly expand software capabilities and lay the foundation for future business growth. However, integrating such technologies is possible only for software based on modern architecture and components. Only by modernizing your legacy system will you be able to leverage cutting-edge technologies for the benefit of your business.

How can you update a legacy system?

Once you decide to revamp your legacy system, it’s crucial to choose a suitable way to do it. At first glance, it may seem that you only have two choices:

  1. Revolutionary way — abandoning your old system and building a brand-new one
  2. Evolutionary way — rebuilding what you already have

In the next section, we explore the main approaches to gradually modernizing a legacy system. After that, we take a look at when it’s better to rebuild your software from scratch.

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How to modernize your legacy systems: 8 approaches

If your current system is still working but not as efficiently as it could, it’s worth modernizing it. The challenge is to integrate new elements into the existing system while being able to use what you already have. To pull this off, you’ll need experts in enterprise system architecture and talented software engineers.

But first, your team needs to choose the most suitable modernization option. Let’s discuss the eight main approaches to modernizing enterprise legacy systems.

approaches to modernizing legacy systems

1. Adopt a microservices architecture

The more components and features your software has, the harder it is for your team to manage it. Since each feature and piece of functionality is connected to others, your developers have to be extra cautious each time they introduce changes. Your quality assurance (QA) engineers will put much time and effort into making sure that updates don’t affect the product’s performance.

One way to prevent these issues and optimize your software development process is by choosing a microservices architecture. This way, you can turn groups of features into separate services that will connect with each other and the main system through APIs. Since microservices are independent units, your team will be able to easily and efficiently update any functionality without affecting other parts of your system.

At Apriorit, we have experience migrating monolithic platforms to microservices architectures that we design. For example, our engineers used the microservices approach to help our client improve the performance, stability, scalability, and user experience of their SaaS property management solution.

2. Rehost the system

This approach means moving part of your system to another physical, cloud, or virtual server. When rehosting, you don’t recompile the code, modify any features, or alter the architecture. Rehosting is a great solution for legacy systems that have scalability issues.

Migrating your legacy software to the cloud can help you improve the product’s agility, scalability, and flexibility. It can also be cost-effective in the long run, as you don’t need to purchase and maintain extra hardware. Cloud hosting allows your DevOps managers to increase and decrease computing power and other resources on demand.

Your team should carefully prepare for rehosting processes when choosing a cloud computing or virtualization approach. It’s crucial to keep in mind various risks associated with cloud hosting, like the risk of traffic spikes. Your engineers need to consider business logic, budget, expected number of users, and requests per minute to make sure you both receive an efficient product and don’t overpay. At Apriorit, we discuss all nuances beforehand and even prepare several budget proposals if the traffic load is unclear.

3. Change the platform

Platform migration, also known as replatforming, means moving an application component to a new platform without making significant changes to the code, its structure, or its functionality.

Say you need the core functionality of your legacy system to work better. A platform migration strategy can help you leave key functionality as is while integrating new services that are compatible with the new platform.

Replatforming only your core functionality will allow you to keep your business processes running while winning time to work on other parts of your platform. This approach also optimizes costs and offers basic cloud functionality.

At Apriorit, we have experience successfully migrating software of different types and complexity to different platforms and know the challenges that can occur during this process. If you’re interested in database schema migration, make sure your team carefully chooses the approach: database first, code first, or model first. 

4. Refactor your code

Refactoring is part of software maintenance, and its goal is to make code simpler, more readable, and more maintainable. By refactoring, you get rid of excessive and redundant code. This makes it easy for new members of your development team to grasp what your software is doing. Refactoring code is something you should do on a regular basis. 

This approach also helps you optimize your software, making the code more logical. Because refactoring is performed in small, gradual steps, the risk of breaking something in the system is rather low, so you won’t need to stop your current business operations to improve your code. Since code refactoring leads to improved software efficiency, your end users also win from such an approach.

The only time refactoring won’t help is if your project’s architecture doesn’t correspond to your business goals whatsoever and the code is so cluttered that it’s hard to do anything about it without breaking the whole structure. In this case, consider rebuilding your system from scratch.

At Apriorit, we often have long-term projects that involve improving legacy systems and refactoring their code. One of the frequent challenges is conducting preparatory refactoring to handle legacy code. The secret to handling this code is to divide the process into three main steps: reduce the size of the code base, bring the source code in line with a single style, and align the code with new standards.

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5. Build a new architecture

Sometimes, poor engineering decisions lead to the release of software with an unsuitable architecture. Other times, an architecture that worked great for a couple of years is no longer enough and can’t support your current technological needs.

A new architecture can significantly improve your software’s scalability and open new capabilities for integrations. With a new architecture, you can adopt technologies and approaches like DevSecOps, microservices, containers, and service meshes.

However, changing the architecture is a challenge because it’s the backbone of your system. Rebuilding or redesigning an architecture requires your team to rewrite the legacy application’s code from scratch in a fully modernized environment. This is also probably the most time-consuming of all approaches we’ve mentioned. On the upside, rebuilding the architecture can help your business gain a more flexible system with better performance and lower operating costs.

Helping clients build a new architecture for their systems is not a new task for Apriorit software engineers. One of the main options we offer to our clients is improving an application’s code by combining principles of the Clean Architecture and Command and Query Responsibility Segregation approaches. By following these principles, we help clients receive solutions that work fast and have few to no bugs. It’s also easy to enrich such applications with new features or modifications of existing ones without compromising the performance and security of the entire solution.

6. Replace what doesn’t work

A legacy system replacement strategy suggests replacing components that don’t work, slow down your operations, or don’t correspond to your goals. Common options for replacing a component are either to build it from scratch or to use an off-the-shelf product such as a software as a service (SaaS) solution.

On the one hand, building a component yourself will ensure you have exactly what your business needs. Custom software is always more flexible and secure. However, a ready solution won’t require any time for development (except for integration), and you won’t need to support it.

At Apriorit, we strive to help our clients improve their systems using a reasonable amount of resources. That’s why our experts carefully analyze whether it’s better to create a component from scratch or integrate third-party functionality depending on the project’s specifics. If the best solution is to choose external services, we recommend paying attention to the most suitable third-party API integrations. It’s crucial to choose the right API protocol for your third-party integration and know tips and tricks for effective integration.

7. Ensure continuous modernization

For many software products, continuous integration / continuous development (CI/CD) processes are key to long-term efficiency. However, legacy systems usually aren’t designed to support continuous delivery.

Since data and functions in legacy applications are key to digital business initiatives, one way to smoothly introduce changes to them is by using a continuous modernization approach. The goal of this approach is to detect, prioritize, and fix issues that create obstacles to your product achieving its primary business goals.

By leveraging continuous modernization practices, your team can focus on gradually overcoming the most problematic business obstacles. It’s important to focus heavily on the delta between the current state and the future state of operations. The main challenge is that modernization is a continuous effort, so your team will have to balance short-term gains and long-term goals.

Supporting and gradually optimizing systems has already become a routine for Apriorit developers, as many of our clients entrust their projects to us for the long term. However, we also receive requests to help with existing products. One of Apriorit’s many successful stories is taking over the maintenance of a client’s legacy data management system and solving several modernization challenges. As a result, we helped the client keep end users satisfied with the legacy software by fixing issues reported by end users and developing custom features that they requested.

8. Adopt modern technologies

Investing in cutting-edge technologies is a proven way to extend the capabilities of legacy systems. These include robotic process automation (RPA), AI, ML, and the blockchain.

By integrating RPA tools into your system, your team can improve the user experience, automate simple tasks, and simplify integrations with data and technologies that are newer than the current system. AI and ML can help with automating data analysis and decoding.

The biggest challenge of this approach is to identify what functionality of your legacy systems you can upgrade with a new technology, which technologies to choose, and how to integrate modern functionality into an outdated system.

At Apriorit, we have skilled AI and ML developers with experience creating solutions from scratch and implementing AI-driven modules into existing products. In one of our many cases, our engineers helped the client enhance their platform with new AI-based text processing functionality for translating, formatting, and generating texts upon a user’s request. As a result, we successfully implemented three powerful AI-based modules into the client’s solution, helping them gain a competitive advantage in their niche.

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When to build a new system from scratch

Choosing the revolutionary approach is the most radical way to modernize your legacy system. While it isn’t always necessary, sometimes you may have no other choice: for example, if your current system is overloaded, there are already inevitable security risks, or the system can’t sustain itself any longer.

Though this approach is costly and time-consuming, it’s the most effective way to completely revamp your current system. By rebuilding a system, you can start implementing new technologies and approaches to your business processes right away. For example, you can build your system to be cloud-first or use a new technology that you couldn’t previously implement without breaking the system.

Here are a few major scenarios when you should consider total legacy software transformation:

  • Your current system can’t support changes required by the market
  • Your vendor no longer supports your system’s technology
  • The cost of licensing your current software is too high, while other companies provide more cost-effective options
  • You’ve acquired another company, and now you need to merge two systems into one
  • You’ve chosen a path of aggressive expansion and need the latest technologies to support your strategy and go way ahead of your competitors

When deciding whether to rebuild your legacy system, make sure to analyze not only expenses but also business benefits. Creating a completely new system can help you:

  • Get a competitive advantage while offering customers brand-new and solid software
  • Remove constraints imposed by old components, resulting in improved flexibility in terms of both design and architecture
  • Easily integrate new technologies
  • Invest in your product’s future, as new technologies will stay relevant for at least another 5+ years

Note: Complete modernization is suitable only for mature companies that can invest in constant IT support and have enough engineers at their disposal. If your in-house team doesn’t have the required skills and experience, consider outsourcing system modernization to a professional software development company

How to choose the best modernization strategy for your system

The ultimate challenge on your way to updating legacy software is choosing a strategy that will lead to the desired results in the shortest time.

The best way to choose is by consulting technical experts. You can start by answering a few questions that will make the process easier and prepare you for a consultation with software engineers.

questions for choosing a modernization strategy

1. What is working well in our current system?

Maybe you have a hard time integrating something new into your legacy system because of old technologies, but the system itself works fine. Or at least it helps your users complete daily tasks without much hassle. Make a list of functions your legacy system currently handles well, as it’s vital to first change parts of your software that are holding your business back. 

2. What is our deadline?

Think about how much time you can afford to spend on modernization if some of your processes have to stop temporarily. Your deadline will also define your modernization approach. For example, if you’re in a hurry, you’ll most likely choose to replace a certain module with an off-the-shelf solution instead of developing your own custom module.

3. What are the goals for system modernization?

Do you want to make your system work faster, decrease maintenance costs, or transition to new technology so you can use AI or big data in your business? Each of these reasons will dictate a different approach to upgrading your legacy technology. Write out your goals and the main issues you have with your current software. Then, your outsourcing development team will analyze all the requested changes, prioritize the most urgent ones, and create a backlog of tasks.

4. What steps should we take to achieve those goals?

This is a big-picture question that will allow you to figure out your strategy. New technologies, new modules, a reduction in spaghetti code, or a new platform should correspond to goals you’ve previously defined. You’ll need to consult experts to fully answer this question, as they’ll help you choose the best technologies to meet your goals. However, you may already know some steps you absolutely need to take.

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Challenges of modernizing legacy systems

Apart from requiring time and money, legacy system modernization can hide challenges that vary from project to project. The most common issues to be prepared for include:

challenges when modernizing legacy systems
  • Disrupted business processes. If your legacy enterprise software consists of multiple systems, simultaneous modernization can negatively affect the work of the entire solution. In this case, it’s best to break the modernization project into smaller chunks of work, updating only one or a few systems at a time. To ensure a smooth workflow, your project managers and development leaders should carefully analyze the scope of work and prioritize tasks.
  • Troubles handling legacy code. Even if some parts of old code seem irrelevant, they should still be handled and updated with care, as you never know what can cause the system to break. Also, if a system contains code written in old languages or uses outdated methodologies, your managers need to carefully plan time for rewriting or refactoring. Since such a process is error-prone, working with old code can make the modernization process take even longer than expected.
  • Risk of data loss. Preserving integrity and consistency when transferring data from legacy systems to new platforms is tricky. Your developers must ensure that underlying software meets data interchange requirements of the new platform. Sometimes, it’s not possible to transfer all data from an old system to a new one, causing significant data loss, so your team has to be ready to come up with creative solutions to prevent these issues.
  • Bad user experience. While your team modernizes your system, there’s always a risk of failure in either individual functionality or the entire product. If your product is still in use during the updating process, your users are likely to experience issues. And when your software is finally modernized, some users may resist using or struggle with the new system, as they are accustomed to legacy interfaces and workflows. To overcome this challenge, we recommend delivering updates one by one to help users gradually get used to the updated software.

To prevent issues caused by the challenges mentioned above and identify other issues of legacy system modernization, make sure to gather a professional engineering team. Go with a software development company with practical experience in similar projects. This way, you will significantly increase your chances of experiencing a smooth workflow and having your systems ready within the planned budget and timeframe.

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How Apriorit can help you modernize your legacy system

At Apriorit, we use both time-proven and new technologies to enrich clients’ solutions with the best combination of reliability and functionality. Our engineers continue to support clients’ projects years after their release. We know how to maintain everything from web solutions to drivers as well as when to suggest global upgrades for the benefit of our clients.

Modernizing a large legacy system is complex and tricky. We carefully explore each project before building the workflow to make sure we can address all challenges and modernize your legacy code efficiently.

Here’s an example of how a common modernization process looks at Apriorit and what we do during each project stage:

Stage 1. Define business goals– Define your current business goals and determine ways in which your software doesn’t fulfill them.
– Analyze your business processes and suggest technologies and features that are lacking.
Stage 2. Analyze your existing software– Sign a nondisclosure agreement.
– Perform a code audit if needed to figure out if parts of your software need refactoring, rewriting, or other work.
– Review your software architecture and determine issues holding back your business and technical development.
Stage 3. Map modernization requirements– Create a technical specification with new features, requirements, and technology platform suggestions.
– Analyze factors like the overall state of your software, your goals, business processes that can’t be interrupted, and software components that need to be modernized first.
– Choose the best strategy for modernizing your legacy system and establish a clear modernization plan.
Stage 4. Develop and refine– Gradually modernize your system according to the agreed strategy.
– Test all alterations to your code to make sure business processes aren’t interrupted and new solutions are of high quality.
Stage 5. Assure quality– Ensure continual testing alongside development.
– Perform full regression testing after altering each module.
– Check software licenses, connectivity, and the work of databases.
Stage 6. Train and onboard– Provide training to ensure you can use the software without any issues and can pass knowledge to your users.
Stage 7. Maintain and support– Introduce updates to support new operating system versions, libraries, and third-party services.
– Conduct regular testing and security audits.
– Integrate additional services according to your business needs.

When leveraging dedicated Apriorit teams to revamp your legacy software, you gain access to a wide pool of experienced professionals, including:

  • Business analysts
  • Software architecture specialists
  • Software developers
  • Data analysts and database architects
  • QA and testing engineers
  • UI/UX designers
  • Technical support managers


Postponing modernization of legacy systems can make businesses suffer from unproductive processes and lose money on endless and costly maintenance. Updating your software helps you drastically improve the system’s security, efficiency, and reliability. Moreover, with modernized software, it will be easier for you to adopt cutting-edge technologies and integrate advanced third-party tools.

To revamp your legacy software, it’s crucial to carefully choose the modernization approach, keeping in mind your business goals, current system capabilities, and user needs. Consider outsourcing such processes to software engineering companies with relevant experience to ensure the right choice of modernization approach and successful modernization.

At Apriorit, we have professional development teams with expertise in both creating complex custom software and improving existing systems.

Ready to give your legacy system a new life?

Reanimate your outdated software in an efficient and pain-free way. Leverage the expertise and skills of Apriorit engineers to carefully plan your system’s modernization and achieve the desired results.

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