Delaying your legacy software modernization isn't an option in today's competitive market.

It’s been years since your company’s last major software upgrade, and the magic is starting to wear off. Noticeable slowdowns, a cap on scalability, and a lack of modern features are some of the signs that it’s time to breathe life into the aging software system.

But before you rush headlong into the upgrade process, it’s important to choose the right legacy software modernization approach. This choice will define how much time, money, and effort you’ll have to invest, as well as how usable and functional the final product will be.

In our article, we’ll explore your options and help you pick the best legacy software modernization approach that suits your business. We’ll also touch upon the challenges associated with modernizing your software so that you’re better prepared to face them when the time comes.

Let’s start from the top and discuss the types of legacy modernization strategies you can employ when planning for the big move.

Key strategies for legacy software modernization

Choose one of the two strategies for legacy software modernization.

What is a legacy system? There is no universal definition, but in general, it’s a system that’s failing to achieve an organization’s business goals and is essentially impeding its growth. It could be due to limited compatibility, poor performance, complicated maintenance, or other reasons. Most often, obsolete architecture and technology are the culprit, and modernization is aimed at rectifying these problems in the first place.

So, we know what to fix, but how do we go about it? There are two main strategies: evolutionary vs. revolutionary modernization. Let’s explain what those terms mean.

Revolutionary modernization

As the name suggests, this strategy involves deep systemic changes over a short period of time. It’s a complete overhaul of the legacy software infrastructure, where the new system completely replaces the old one.

To successfully apply revolutionary methods, you have to be aware of the significant amount of work and the expenses this kind of transformation usually requires. A number of factors may justify your decision, such as:

  • you’ve accumulated too much technical debt to hold on to your legacy system
  • your company is going through a major change that calls for an immediate makeover of the software
  • your old system has serious security issues and is becoming a liability
  • the software you’re using isn’t supported by the vendor anymore

The list goes on, but you see the general tendency, right? Revolutionary modernization is mostly a last resort method for dealing with complex legacy issues that need to be resolved urgently. Although using this strategy is sometimes inevitable, it may incur high costs and create additional risks for the business.

Luckily, there are other options.

Evolutionary modernization

Taking the evolutionary route means making gradual, iterative changes to your legacy system. This way, you can even out the cost of the transformation while keeping your systems operational in the process. Updating one service at a time, your IT team can dedicate more resources to resolving individual issues instead of trying to tackle them all at once.

Here are some typical scenarios where you’d want to use the evolutionary strategy:

  • your high-risk operations cannot be interrupted during the upgrade
  • you need to address several critical issues but can’t afford to do so simultaneously
  • your monolithic application is too bulky to be redesigned quickly, so you need to do it bit by bit

Evolutionary modernization of your outdated software is a process that requires careful planning. By using this strategy, you can minimize risks and ensure a smooth transition to a new system.

Now that we’ve covered your strategy choices, let’s move on to particular legacy modernization approaches.

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Choosing a legacy system modernization approach

There's an abundance of options when it comes to selecting a legacy software modernization approach.

While there are only two general strategic paths you can take, when it comes to modernization approaches, there’s plenty to choose from. Each of these methods allows you to handle code and infrastructure in its own unique way. This variety may be confusing at first, so we’ll describe each approach in detail, pointing out the differences and advantages.


When you have a solid codebase that has become outdated but is still performing its main functions well, encapsulation can be the way out. Keeping the most critical functionality intact, you can wrap it in new code and integrate it with a modern user interface and database access via APIs (Application Programming Interfaces).

The resulting software will have a refreshed look and much better compatibility with third-party components but will still carry most of the obsolete code underneath. One of encapsulation’s main benefits is the relatively low cost of modernization.


Rehosting is the process of transferring your application to a new environment. While the code remains untouched, the newer infrastructure (a newer physical server or cloud storage) can give your software a serious performance boost. Rehosting is one of the safest and quickest ways to modernize your legacy system and improve its efficiency. As no changes are made to the codebase, it’s actually considered to be a simple migration. However, keep in mind that the solution will still inherit most of the limitations of the original software.


This is another legacy modernization approach that is pretty straightforward in its nature. It boils down to porting the code written in older languages like COBOL to new environments. It takes some time and effort, but it’s nothing extraordinary for an experienced software developer.

By using this technique, your company can quickly achieve better compatibility and lower the cost of maintenance. At the same time, the main functions and business logic of your software will be preserved.


Refactoring essentially means optimizing the original code. By removing bottlenecks and inefficiencies, a team of skilled developers can eliminate or reduce technical debt, taking your clunky legacy system to new levels of performance.

Refactoring doesn’t alter the software’s external behavior, so your users won’t have to go through additional training.


This is one of those legacy system modernization approaches that are a bit tricky and require advanced expertise. It involves making major changes to the code to adopt a new architecture. For instance, to switch from a monolithic app to microservices.

What you get is a completely revamped application that is compatible with most modern services, has better performance and scalability. Since the modifications of the codebase are more drastic, you should be prepared for higher costs and potential risks.


It takes a massive effort to completely reengineer an aging piece of software, but it may be well worth the trouble. Changes are made to the codebase at the deepest level, and you can leverage that to optimize business logic, remove redundant features, and add new ones.

The end product will be an entirely different beast in terms of performance, functionality, and integration capabilities. Instead of having to put up with limitations, you’ll be able to enjoy the full benefits of a cloud-native app with functions that are easily extendable through third-party solutions.

By the way, Acropolium is no stranger to software reengineering. We’ve completed multiple projects where we rebuilt our clients’ software from the ground up, creating custom solutions.

Are you surprised there are so many options to consider? Our next section sheds some light on the thought process behind making your choice.

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Which approach is going to work best for your business?

Picking the best legacy modernization approach for your business needs can be tricky.

Businesses that endeavor to modernize their legacy systems experience a fair amount of pressure from stakeholders and competitors. Having to choose the right upgrade method is another headache for many. But careful consideration of every option, of the pros and cons of each approach, is what makes all the difference. It’s about finding the best balance between the benefits of the transition, the risks, and the cost and time that are needed to complete it.

To make your life a little easier, we’ve prepared some recommendations on how to make that decision. Actually, it’s more of a list of steps:

  • Assess your legacy system’s state. What are its strengths and weaknesses? What critical functionality does it lack? Are there security or compatibility issues? This initial assessment will help you get a clearer view of the actual impediments your legacy system creates for your business and your customers.
  • Set priorities for the modernization process. What needs to be changed urgently for your company to stay afloat or gain an advantage in the current market? Are there areas where your system’s performance is still satisfactory? Is migration to a new platform a whim or a necessity for your business?
  • Consult with tech experts. From this point, going forward without professional legacy software modernization consultations and support can be risky. Let us explain: you’ll need an expert’s opinion on your system’s technical debt, performance bottlenecks, the best choice of architecture to switch to, and a million other issues.
  • Define your budget and determine time constraints. Knowing these two variables is crucial in order to find the best solution. There are always limits, and with the help from your tech partner, you’ll have to navigate those waters, looking for the most efficient way to achieve your goals.
  • Choose your approach and create a modernization roadmap. Working closely with tech experts, take into account all of your pains, prioritize and strategize to achieve maximum effect. Whether you’ve decided to migrate to a new platform, refactor your legacy code, or start a major do-over, commit to the process and consistently follow your plan.

It’s impossible to advise you on the choice of a modernization approach without knowing the specifics of your business and the current condition of your legacy software. But it would also be unwise for you to move forward without first obtaining professional advice, so if you can, start looking for that tech partner.

In the meantime, we’d like to share some more insights.

Common challenges of legacy system modernization

You're likely to encounter a number of challenges in the course of modernizing your software, but there are ways to avoid them.

Your transition to the new system is sure to be a success, but you’re likely to encounter several obstacles on the way. We took the trouble of listing the most typical ones.

Data management and security concerns

Any substantial change to the codebase can lead to potential data security risks. It is also the case when you transition to a new environment like cloud services. The transfer of your legacy data must be supervised, and proper governance and security controls need to be in place to prevent data loss or breaches. Your tech team’s experience in cloud solutions is a valuable asset at this point.

Stakeholder resistance

It can be difficult to reach a consensus among key stakeholders regarding the necessity of modernization. As long as the legacy system doesn’t fail completely, decision-makers may be reluctant to allocate funds for its upgrade. Convincing them that the investment is justified is a tough job for a CTO. However, it’s important to understand that such upgrades are unavoidable and can’t be delayed, as their cumulative cost increases over time.

Low quality of the source code

Most modernization techniques are very sensitive to the quality of code. That’s why a preliminary assessment by a team of software engineers is a must in order to produce a realistic estimate. Otherwise, what started as a one-week job may turn into months of tedious rework and bug fixing.

Poor choice of modernization technique

Trying to save costs during a modernization is understandable, but in some situations, it may do your business a grave disservice. Choosing partial measures like encapsulation or replatforming may lower the cost temporarily, but if the system requires a complete overhaul, those solutions won’t be sustainable in the long run. Furthermore, when the time comes to reengineer the system, the total bill will likely be larger.

The truth is that most of these pitfalls can be avoided. We say it with certainty because over the past ten years, Acropolium’s team has successfully delivered almost 60 legacy modernization projects.

Acropolium’s experience

We offer a full range of modernization services, including replatforming, refactoring, and a complete redesign from scratch. When you partner with Acropolium, you can expect the highest quality of service across a full cycle of professional support — from initial audits and consulting to the actual modernization and performance testing.

With our help, your outdated system will transform into a performant, future-proof solution that will be compliant with modern security standards. Our portfolio includes projects from every industry, such as HoReCa, automotive, healthcare, and more.

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Summing up

The software your business runs on can either be a benefit or a burden, and as your system ages, the line can get blurry. Recognizing the need for an upgrade while it’s not too late is the first step toward successful modernization. The next part is about selecting a strategy and navigating your way through various legacy software modernization approaches. After all those forks, you’ll finally be on a straight course to your upgraded system, ready to reap the benefits of scalability, performance, and new features.

At this point, all you need to ensure success is an experienced software partner. So get in touch with us, and let’s start the journey.