Best Legacy Application Modernization Strategy Guide

Updating the system established in a network or in an organization may be considered a part of change management. The goal is to enhance the user experience while maximizing the efficiency of the application, which can achieve solutions more seamlessly. However, bringing the change is not child’s play, and it follows a complete legacy modernization strategy.

Legacy application modernization is the process that refers to replacing the outdated system to bring a more updated version for cloud-based applications. This process is not about replacing the whole system only, but adding some new features to the existing system for improvement also works pretty well. Activities may include enhancing the front end, making the design more responsive, and reducing loopholes in the network systems.

But there is more to implementing a whole new, updated and changed version of software. Therefore, we have written a complete guide on some of the best legacy application modernization strategies to help you understand how you can implement a more updated version of a system in an organization.

What is Legacy Application Modernization?

Legacy application modernization is the method of digitally transforming legacy processes, IT systems, or applications to set the organization and remove data silos on the path to data authorization. Digital modification is the organization’s broader effort to enhance efficiency and become more driven by growth or innovation. As part of the digital modification, a legacy application modernization strategy settles the technology branch of the people-method-technology triad. You evaluate the requirements of your business, decide what to modernize first, make a plan, and implement it.

Legacy Application Modernization Strategy:

In the process of modernizing legacy applications, the initial step in building the business case involves assessing the existing applications and the systems they rely on. Subsequently, these applications are ranked based on their benefits, costs, and associated risks. To evaluate legacy systems and determine the most appropriate approach for application modernization, organizations should follow a comprehensive strategy:

Retain (Encapsulate)

Retain (Encapsulate) is a modernization strategy that involves holding key components of a legacy application that are conserved or repurposed within a novel architecture. This legacy software is encapsulated, enveloped, and subsequently accessed as a service through APIs.The encapsulated legacy components are made accessible as services through APIs, allowing them to be seamlessly integrated with newer systems. Additionally, this strategy also paves the way for potential future expansion of the application using a microservices system gradually.

Rehosting (Lift and Shift)

Rehosting involves migrating the application to a different infrastructure without making significant changes to its codebase. This strategy is beneficial when the main goal is to move away from legacy hardware or data centers while retaining the application’s current functionality. While rehosting provides short-term benefits, like reduced maintenance and infrastructure costs, it might not fully capitalize on the advantages of modern cloud-native architectures.


Replatforming, or “lift, tinker, and shift,” involves moving the application to a new platform while making minor adjustments to improve its performance and scalability. This approach allows organizations to leverage cloud services and technologies to enhance the application’s capabilities. While it offers a balance between immediate benefits and modernization, it might not address all underlying issues of the legacy application.

Read Also: Essential Tips to Secure Web Application Server

Refactoring (Rearchitecting)

Refactoring, or rearchitecting, involves restructuring the application’s codebase and architecture to align with modern design principles. This approach aims to improve maintainability, scalability, and efficiency. While more resource-intensive, refactoring offers long-term benefits by enabling the application to adapt to changing requirements and integrate seamlessly with new technologies. Microservices architecture, containerization, and serverless computing are often utilized in refactoring strategies.


Rebuilding entails recreating the application from scratch while retaining its core functionalities. This approach provides the opportunity to leverage the latest technologies, frameworks, and development methodologies. While it offers the highest level of modernization, it is also the most resource-intensive and time-consuming strategy. Rebuilding is suitable for complex legacy code applications that hinder efficient modification or extension.


Replacing the legacy application involves adopting a new commercial off-the-shelf (COTS) solution or custom-built application that meets the organization’s current needs. While this strategy provides an opportunity to start fresh with modern technologies, it also requires significant effort in data migration, training, and change management. Replacing is suitable when existing solutions can adequately address the legacy application’s functionalities.

Challenges of Legacy Application Modernization Strategy

Legacy applications often pose significant challenges to businesses striving to remain competitive and efficient. These applications, built on outdated technologies and architectures, hinder agility, scalability, and security. To address these issues, organizations undertake legacy application modernization strategies. However, this endeavor is not without its hurdles. Below we describe challenges that businesses commonly face when modernizing legacy applications.

Complexity and Understanding

Legacy applications have usually grown in complexity over the years, often with a lack of comprehensive documentation. Solving the complexities of these systems is a challenging task that makes it difficult for developers to gain a complete understanding of the application’s logic, dependencies, and business rules. This complexity interferes with the modernization process and increases the risk of introducing errors during migration.

Integration with Modern Technologies

Legacy systems were not designed to integrate with modern technologies and platforms seamlessly. Attempting to integrate them with newer applications, services, or cloud infrastructure often leads to compatibility issues. This can result in data loss, security vulnerabilities, and overall instability.

Cost Considerations

Modernizing legacy applications can be a costly endeavor. Organizations must allocate resources for development, testing, training, and potential downtime during the transition. Balancing the financial investment required for modernization with the potential benefits in terms of efficiency, agility, and reduced maintenance can be challenging, especially for smaller businesses.

Disruption to Business Operations

Legacy application modernization often requires changes to core processes and workflows. This disruption can impact daily operations, causing downtime, decreased productivity, and potential customer dissatisfaction. Minimizing the impact on business continuity while implementing changes is a delicate balancing act.

Skill and Knowledge Gap

Modern technologies and development practices might differ significantly from those used in legacy systems. Developers familiar with older programming languages and architectures may not possess the necessary skills for modernization. Bridging this knowledge gap through training or hiring new talent can be time-consuming and resource-intensive.

Security Risks

Legacy applications are more susceptible to security vulnerabilities due to outdated security practices and unsupported components. Ensuring that the new system meets modern security standards is crucial during the modernization process. Failing to address security risks could lead to data breaches, compromising sensitive information.

Final Verdicts 

Legacy application modernization is a strategic imperative for organizations aiming to stay competitive in the digital age. Choosing the right modernization strategy requires a deep understanding of the existing application’s complexities and the organization’s business goals. Whether through rehosting, re-platforming, refactoring, rebuilding, or replacing, the chosen strategy should align with the desired level of modernization and the resources available. Ultimately, a successful modernization journey requires careful planning, collaboration among stakeholders, and a commitment to continuous improvement. 

Noman Sarwar

Noman Sarwar is highly experienced in creating engaging content that adds real value to a blog, website or brand. He is creating content for multiple niches like technology, SEO, Marketing, Health, Education and Career Development etc. Let the right words be offered to the audience in a great way that has the potential to ensure success and get something you are looking for.

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