What does the legacy software mean and how to verify your system require more attention? 

Legacy application as an information system that may be based on outdated technologies but is critical to day-to-day operations.  It may refer to applications, platforms, tools and programming languages that  required to be replaced by modern technologies.  

Initially, the software is developed to solve specific business problems according to existing requirements based on selected technologies. The typical reasons for modernization are lack of maintenance, changing business requirements and inability to implement required tasks within the legacy framework/technology.  

Any system or application has its own lifespan which often depends on the desire and capabilities of the software vendor to support it and constantly update. In fact, it does not necessarily defined by its age.  

As soon as the vendor refuses to support the software product, end users are forced to update it themselves in order to meet the operational demands or changed business conditions. Very often the need to modernize a legacy system occurs due to the certain limitations or lack of functions that the software should perform.  

It may also include the low performance, incompatibility with other systems or outdated user interface. Depending on the type of system and its main tasks, over time, new requirements may also arise regarding user access to the system (e.g. users need to access the system through the web, tablet, or mobile devices). 

Identifying legacy software 

How to identify there is an issue with your software system? There are many factors that can determine whether you should take an action and create the roadmap for the new.  

0.1 The system is slow and does not perform as expected 

In case the system is slow, standard activities take hours to perform and the overall system is becoming cumbersome, the lack of performance is clear – the reason might be that the software or technology is out to date or the quality is low. Consequences can be huge. Can you imagine 200 users spending 20% of their time waiting for the system to deliver information or perform the task? 

0.2 Device-dependent and no mobile-device support 

Nowadays, most of software is created as a web-based application because of two reasons: one is that updates are simple (all users got access immediately to the new version), and second, that users can work on almost any device. Modern applications are designed to be responsive (Responsive Web Design) and more and more organizations, move to the online world or to cloud solutions.  

Working remotely, from the laptop, tablet or smartphone requires the software to be device-independent and available typically online. Even native application (e.g. written on Apple iOS or Google Android needs an internet connection to perform, in order to connect to the database). 

03. Incompatibility  

The software that is not able to integrate with other solutions or is not supported by modern operating systems or web browsers. In the near future, it will require replacement or redevelopment.  

0.4 Software is not user-friendly and hard to learn 

There is a lot of solutions that requires additional training for users (e.g. engineering or design software), but when we talk about day-to-day business solutions, platforms should be created as low-touch solutions and easily accessible for any type of user.  

0.5 Technology is obsolete and/or not supported 

Technology world is rapidly changing from month to month. Having the software developed few years ago, you might face outdated technology (no longer supported) on many levels from the code, to server and user-interface. Great examples are old frameworks that contains deprecated functions or integration interfaces no longer supported by 3rd parties. 

0.6 The software is no longer functional  

All the functions and features that have been useful years ago, might be not needed anymore today. Your current software system that has not been developed by the years to map current processes or needs of users, might not only be legacy but also create frustration because of workarounds that people have to make.  

0.7 You can’t add new features or integrated with new 3rd party solutions 

In case the maintenance of the software is so hard that you can’t add any new feature or the risk of crushing the system is to high, you should consider your software as legacy and this is really critical issue. Expanding the functionality and following business change should be one of the main assumption in rapidly changing world, so instead of creating limitation and barriers, the software should be flexible enough to support organizations and people.  

The risks and costs of legacy technology 

Hire the augmented team to reduce recruitment costs and all office-related spending. Contracts are very often flexible Even though the enterprises are still relying on legacy systems written in outdated technology, the costly consequences and interruptions may come soon. The cost of maintaining the legacy systems is associated not only with technical debt but also with unpredicted risks.  


According to DELL’s research, many organizations devote up to 80% of their IT budget to maintaining the legacy technology and just 20% is left for innovation. The maintenance approach of legacy software can literally drain organizational resources which will ultimately impact productivity and critically important business activities. 


Legacy systems are more prone to cyber-attacks. When the system is no longer supported it means that it also stop receiving new updates for any security vulnerabilities. As a result, hackers can exploit unprotected vulnerabilities and gain access to the systems. Legacy systems may also lack the updated security features which are critical to data protection. 


When an employee leaves the organization, there is a knowledge gap regarding system administration and management. Due to the poor user experience organizations must invest much more time to onboard and train new employees or customers to use legacy systems. In this case, modernized systems tend to be more intuitive and easier to maintain. 

Missed business opportunities 

As mentioned earlier, due to the legacy maintenance, organizations devote little budgets to innovation and integration with/of new technologies. However, it is not the only reason that may decelerate business scalability and growth. The point is that even if the legacy systems can meet internal organizational needs it can be inappropriate to changing customer behavior and growing customer service expectations. 

Preparing for the modernization project 

Legacy software modernization is a frequently challenged and long-time project. However, it should pursue the main goal – cover current and future (short-term, related to plans) organizational needs. Before undertaking any development paths it is better to start with creating the roadmap to define objectives for the modernization project.  

A clear understanding of the current application status, its technical constraints and what tasks it should cover determines most of the overall project success. The application assessment usually includes analysis of the structure, system functionality, performance, stability, redundancy, user interface, databases and system outputs. 

There is also another factor related to people and organizations, that the project impact on many areas. New applications, data structures, data defragmentation and preparation, integrations, choosing the technology can be as long, as risky when there is no leadership on board. 

Look at the project from a holistic point of view: 

  • What approaches to the modernization process might be chosen and which you consider as the best one? 
  • What are the main goals in the legacy modernization project and what do you want to achieve – how you can measure success?  
  • What costs and time are needed (and available) to achieve the modernization goals? 
  • What are the current software architecture and ecosystem (how many systems do you have, how they are connected, which of them do you replace, where are the data sources)? 

Preparing budget and timeline 

The budget preparation and the timeline have to be both flexible and realistic. Expectations to make the change quickly can ruin the whole preparation and effort of people making the modernization. The typical considerations when making the transformation are related to the product fit (how the solution fit to the needs), the overall cost of ownership (not only the cost of license or development but overall cost by the years), technology currency and the implementation time. 

Approaches to legacy software modernization 


This approach implies rewriting the application or system component (or as a whole) from scratch while preserving its scope and specifications without changing the system functionality. 


It includes restructuring and optimization of existing code without adding new components in order to simplify the system and remove unnecessary elements from it. 


Application or component migration to a new platform. In this case, there is no need in rebuilding application but just in tailoring it to the new targeted environment (typically cloud-based). 


It means significant changes in the application code so it can be shifted to the completely new and modern architecture (e.g. popular microservices). This approach is similar to re-building the application from scratch but with an assumption that the architecture also is changed. 


This approach is used if there is no reason to invest in application or component modernization. As the result it replaced by new one that meets new requirements. It is worth mentioning that all these strategies are not mutually exclusive, and different strategies can be applied to specific parts or elements of the system.