Anastasiya Bulykina
Anastasiya Bulykina
B2B Marketing Manager
November 2021, 7 min. read

What does the legacy software mean?  

A legacy application is an information system that may be based on outdated technologies but is critical to day-to-day operations.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 are 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 lifespan, which often depends on the desire and capabilities of the software vendor to support it and constantly update it. It does not necessarily define by its age.  

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

It may also include low performance, incompatibility with other systems, or an outdated user interface. Depending on the type of system and its main tasks, 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 if there is an issue with your software system? Many factors can determine whether you should act and create a roadmap for the new one.  

0.1 The system is slow and does not perform as expected 

If the system is slow, normal activities take hours to perform, and the overall design becomes cumbersome, the lack of performance is apparent – the reason might be that the software or technology is outdated or the quality is low. The consequences can be enormous. Can you imagine 200 users spending 20% of their time waiting for the system to deliver information or perform a task?  

0.2 Device-dependent and no mobile-device support 

Nowadays, most software is created as a web-based application for two reasons: updates are simple (all users get access immediately to get an updated version), and users can work on almost any device. Modern applications are designed to be responsive (Responsive Web Design), and more organizations are moving to the online world or cloud solutions.  

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

03. Incompatibility  

The software cannot integrate with other solutions or is not supported by modern operating systems or web browsers. Shortly, it will require replacement or redevelopment.  

0.4 Software is not user-friendly and hard to learn 

Many solutions require additional user training (e.g., engineering or design software). Still, when discussing day-to-day business solutions, platforms should be created as low-touch solutions and easily accessible to any user.  

0.5 Technology is obsolete and/or not supported 

The technology world is rapidly changing from month to month. Having the software developed a few years ago, you might face outdated technology (no longer supported) on many levels, from the code to the server and user interface. Fitting examples are old frameworks that contain 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 were valid years ago might not be needed today. Your current software system that has not been developed over the years to map current processes or users’ needs might be a legacy and create frustration because of workarounds that people must make.  

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

In case the maintenance of the software is so hard that you cannot add any new features or the risk of crushing the system is too high, you should consider your software as legacy, which is a critical issue. Expanding the functionality and following business change should be one of the main assumptions in a rapidly changing world, so instead of creating limitations 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 often flexible. Even though enterprises are still relying on legacy systems written in outdated technology, costly consequences and interruptions may come soon. The cost of maintaining the legacy systems is associated with technical debt and unpredicted risks.  


According to DELL’s research, many organizations devote up to 80% of their IT budget to maintaining legacy technology, and just 20% is left for innovation. The maintenance approach of legacy software can drain organizational resources, impacting productivity and critical business activities.  


Legacy systems are more prone to cyber-attacks. When the system is no longer supported, it stops receiving latest 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 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 onboarding and training 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 

Due to legacy maintenance, organizations devote little budget to innovation and integration with modern 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 change customer behavior and grow 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 a 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’s success. The application assessment usually includes an 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 in many areas. New applications, data structures, data defragmentation and preparation, integrations, and choosing the technology can be 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 do you consider the best one? 
  • What are the main goals of 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, and where are the data sources)? 

Preparing budget and timeline 

The budget preparation and the timeline must be both flexible and realistic. Expectations to change quickly can ruin the practice and effort of people making modernization. The typical considerations when transforming are related to the product fit (how the solution fits 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 from scratch while preserving its scope and specifications and not changing the system functionality.  


It includes restructuring and optimizing existing code without adding new components to simplify the system and remove unnecessary elements.  


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


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


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