Why Modernize Your Legacy Software?

Kseniia Goldovska

Legacy System Modernization: A Complete Guide

Legacy systems modernization is one of the hard but still effective ways to improve your customer acquisition strategy, re-engage the returning customers, and cut costs. The technologies come the long way even in the last 5 years, constantly picking up the pace.  Thus, staying one step ahead of young & bold competitors becomes impossible without the persistent strive for improvement using all the possible options.

Software life cycle graph from release though EOL/EOS date
Source: Product EOL/EOS 2018 Report

Technologies that were on the top five or three years ago become increasingly irrelevant as well as the decision logic and architecture patterns. Customers, inspired by the best user experience practices and stunning web designs require more and more, frequently preferring the brand-new products over the legacy applications.
This is one of the reasons to consider the option of modernizing your old software.


What Is Software Modernization?

Let’s start by figuring out the concept of legacy software. The phrase is defined as outdated methods, technologies, and applications, in general. Thus, legacy app modernization means the replacement of an obsolete software product by the modern one, using the latest tech trends and the properest stack to upgrade your old project. 

Usually, the support of such projects consume a large part of a budget, and the other part is spent on adding new features to meet the customer demands. Thereby, new features are added into the legacy code turning the complex systems into sophisticated ones, interfering with making a decision on application modernization.

IT product spendings graph

In addition, the more you delay taking the final decision, the more complicated it becomes for the team to modernize the application.

“Legacy software is used everywhere”, you may think, “so there is nothing bad in it.” Nothing good either. According to the statistics, now you have the great chance to get ahead of your competitors by modernizing your old systems, while they will be spending much of their time and budget on supporting the legacy application without creating new opportunities for their product.

Reasons for Legacy Modernization

Better Maintenance

The more up-to-date the application is, the easier is to support it. 

Legacy software maintenance consumes much time, budget, and human resources, and what’s worse, their amount will be increasing. 

The cause lies in the monolithic architecture the most legacy software relied on during the development. So, it’s impossible to modify the parts without modifying the whole. It’s evident that modifying the whole requires much more resources. 

Monolithic architecture complicates the process of application modernization

Besides, the real problem of many legacy applications that prevents the teams from optimizing the maintenance process is a lack of modular architecture that enables making changes and adjusting the specific functionality and scaling the project parts that need it the most. 

In a perfect world, the monolithic architecture requires changes to cater for the flexibility of an application. 

Unfortunately, even if your application already contains multiple modules, it can be still considered as legacy software and needs modernization. The next step to turning the functionality into the independent easy to maintain units is the technique of microservices.

This architecture style enables building, deploying, and supporting the autonomous services in isolation from the other system parts without the necessity to interfere in the whole. 

Microservices makes it possible to modernize application segments

Exactly these microservices will considerably simplify regular software modernization in the future.

Cleaner Code

The cleaner code is, the easier is for the developer to work with it. 

Theoretically, the code quality should be such as to enable a developer who knows nothing about the project to open the code and understand its functions. 

A project doesn’t even have to be on the list of the legacy applications to have the code that is far from being perfect due to various reasons:

  • High speed of project development (when the main objective is to outperform the competitors, launching the product faster than the rest of the world);
  • Insufficient skills of a developer;
  • A great number of successive developers who worked on a project;
  • Lack of specifications.

Indeed, legacy app modernization will help you get rid of the most frequent errors:

  • Comments (the well-written code does not require an additional explanation).
  • Code clones resulted from the weak communication between two or more developers who are working on similar tasks or the rush. 
  • Dead code (code that doesn’t perform any functions but hasn’t been deleted for certain reasons). 

Greater Collaboration

The better is the performance characteristics of an app, the easier is for the user to collaborate within the application. 

High load speed, absence of bugs, data security, an option for a user to quickly understand how the application is working or at least the user manual based on the clear app documentation will make the process of collaboration easier. Not to mention the better user experience and application appearance that are the icing on the customer cake.

Clear Project Documentation

The clearer the app documentation is, the easier it will be for a new team to develop or maintain the project. 

Most often, the lack of project documentation, its incompleteness or sophistication become the related components of the legacy systems for numerous reasons.

  1. In many companies, this legacy application became the first major project executed without much experience in creating and managing documentation (or controlling this process). 
  2. Frequently, the speed of project development is a priority to get a competitive advantage, so the documentation management is overshadowed. 
  3. Legacy code entails legacy documentation that should be modernized together with the app. 

Why the documentation is a crucial part of the project? The main purpose of project documentation is to make sure that in the case of emergency one team of developers may leave the workplace, and another team is able to take their place without losing time and compromising on code quality.

    Subscribe to our newsletter

    No spam, only hot&fresh posts from team

    Every month our subscribers get awesome updates

    Stronger Security

    After all, the legacy systems can’t be competitive with the up-to-date software in security issues. Obsolete software products are much more vulnerable to all types of cyberattacks, increasing a user’s chance to become a target of cybercriminals. In this way, by using and proposing to use such systems, you put your customer security at risk. 

    Simpler Integrations

    Integration with third-party services is a must for applications of today. Of course, five years ago the platforms we built didn’t include the integration possibility that’s why to move with the times, you should add this feature. 

    Legacy application modernization brings better security, cleaner code, easy cloud integration and improves cooperation

    Steps to Legacy Modernization

    Architecture Audit

    The best option to start modernizing the software is the audit of the high-level application architecture, components, and functionality. The audit helps detect system bottlenecks, manage the risks, and recommend the most appropriate solution based on the customer requirements that should be met during the legacy software modernization. 

    The application architecture is worth being examined at least to understand what code should be analyzed during the next step. Of course, if the quality of the application is low, it’s possible to identify the majority of mistakes already on the stage of the architecture audit.

    Code Audit

    A comprehensive code audit to detect code errors, identify and analyze the vulnerability of the code, forecast and prevent the detected vulnerability in the future.
    In addition, we shouldn’t forget about technical application support. Unfortunately, no exact statistics are available, but most researchers are positive that approximately half of all time allocated to maintain the application is spent on reading the already written code to add new functionality, fix bugs, integrate into new environments, etc.
    That is why cleaning up the code mess is a must-do during the legacy software modernization for app modification and expand the functionality.

    Performance Testing

    The main objective of the performance testing is the identification of the application’s stability, work performance, and amount of resource consumption, and other attributes of quality in different use scenarios and loads. 

    Such tests allow detecting the flaws and system bottlenecks to define and prioritize the application parts that should be scaled during the modernization, as well as the modernized system work performance requirements. 

    After the legacy system has been analyzed and weak points have been detected, we can move to modernization that may include the following steps: 


    Refactoring is a process of amending the application system in such a way to change only the internal code structure making it simpler and clearer without influencing the result.
    This activity is aimed at streamlining, structuring, and systematization of chaotic (for certain reasons) code, debugging, and improvement of the application performance.

    Unit Tests

    Automatic unit tests are a crucial part of the software modernization process. It would be better if the application is upgraded in the format of short iterations accompanied by writing and running unit tests. Their value lies in detecting the errors right away and ensuring the application’s efficiency. 

    In the perfect world, developers would run these tests each time when compiling to keep the process of app modernization under control.

    Strategies to Modernize Legacy Applications

    Monolithic Architecture to Modules

    In general, most legacy systems are monolithic applications. This fact makes difficult to modernize the app components whether it is scaling a certain part that requires it the most, or adding the functionality. 

    Fact remains that monolithic architecture doesn’t allow changing a system part in isolation. Modifying the functional unit is impossible without modifying the whole structure of the system. Replacing monolithic applications by modular ones precisely for adding flexibility is one of the solutions the modernization is aimed at.

      Want to check the code quality?

      Cloud-Based Integration

      Cloud computing promises a bunch of benefits for businesses, including the possibility of continuous integration and delivery during the process of legacy app modernization.

      The concept of continuous integration & delivery (CI/ CD) offers as its name suggests, the assembly line of code testing and delivery with the opportunity to continuously merge the recently written code in the mainline one. In other words, a developer submits only the small application segment, accompanied by unit tests (as it’s been mentioned above) to make sure the code fulfills the functions envisaged. 

      CI/CD are the vital steps to modernize your legacy application that simplify further support and cycles of updates.


      The software documentation that is a basis of building the modernization strategy when working on legacy tech projects can often be incomplete, obsolete, or absent. Based on our experience, reverse-engineering is the best practice to apply in such cases. 

      The main objective of the reverse-engineering process lays in researching the application design to understand its work principles and mechanisms and find the undocumented features for further project modernization.

      Legacy Application Modernization Services: What Strategy to Choose?

      Working on legacy software modernization is a long and complex process that requires the team to conduct extensive research on the market and technologies available.

      And if the market research could be done in-house, it’s better to leave the project estimate and legacy application audit to the dedicated team of qualified developers, especially if your product is live and has a certain number of users. Choosing the right legacy software modernization strategy is a fundamental decision that shows the direction to further development. 

      The wrong direction will mislead your technical team even if each of them is a real professional with proven experience. This is exactly the reason to search for the consultant who will be able to manage the risks and pick up the proper strategy.

      You may check out the software modernization case study with the real project example. We talk about a vision we’ve drawn upon while developing an approach, based on the custom project characteristics. Anyway, this case may become the starting point for bringing up the idea of software modernization.

      Leave a Reply

      Your email address will not be published. Required fields are marked *