Legacy Systems Conversion & Support

We will evaluate possible updates and conversions of your Legacy systems to one of the more current platforms and if you do decide to update the system, we will execute the updates and/or conversions. We will also support and maintain your Legacy Systems, work on bug fixes and add new features and functionality as directed.

Legacy System Conversion becomes necessary or desirable when newer technology provides sufficient benefits or requirements that make older platforms and data no longer economically feasible to maintain.

Checklist for successful Legacy system conversion:

Here is our checklist of points to consider for a successful Legacy system conversion project:

  1. Assess the current state of legacy systems.
  2. Legacy software does not always fall under “old” or “outdated” definitions. Need to assess all systems in place to uncover the current and potential issues it can cause in the near future.

  3. Select the modernization approach that would deliver value fastest.
  4. Based on the assessment conducted, choose the modernization approach that best fits your needs and will help you deliver results fast.

  5. Rethink the architecture and prioritize for simplicity.
  6. Legacy systems often fail to perform as needed due to their overly complex structure. When modernizing your system, less is more in terms of both architecture and functionality. Start by implementing only the most important features.

  7. Choose the technology to deliver optimal performance & user experience.
  8. When reengineering your system, make sure you use a solid and future-ready technology stack. The right tech stack contributes to building a performant, reliable and efficient product. Adopt a solid quality assurance and testing process to deliver the best results.

  9. Document for future system growth.
  10. To avoid the same mistakes that made you reengineer your current solution, introduce (or adopt best practices used by other companies) a set of coding standards and internal processes. Orderly documented and clean code make your software easy to understand, extend and maintain in the future.

  11. Create a separate support and retirement schedule for your legacy system.
  12. Even if you have a brand-new system running like a clockwork, you will still need your legacy software, just in case. So, don’t kill it all at once. Document and archive your solutions so you can easily access and refer to them when needed. Therefore, you need to support your legacy system for some time and plan for retiring your legacy system only when your new product is up and running.

  13. Budget for training and system updates.
  14. Working with the old systems for years, your employees might need some time and guidance to master the new software. So be ready to invest in staff training for better performance and efficiency. Additionally, plan for regular system updates. If you fail to keep your product up to date, you will soon face another modernization challenge.

Legacy system assessment framework:

Steps to assess the existing solution.

  1. Technologies Analysis
  2. The first step in our plan is to identify and analyze the technology stack of the existing product. Thus, we know if the programming language or frameworks used are still relevant and supported by the vendors. If the product relies completely on outdated technologies, the chances are we would need to completely rewrite it in the process of modernization.

  3. Architecture Audit
  4. In case the tech stack (or some parts of it) is still relevant, it is necessary to conduct an architecture audit. This will help you define the system elements which are functioning well and focus on the ones that need modernization. Plus, you will be able to see how different parts of the system interrelate, so that your future changes won’t affect the whole product.

  5. Code Review
  6. Legacy software usually has an excessive codebase, requiring regular reviews and refactoring. If not treated properly, the software tends to “rot.” This might lead to more design flaws and conflicts as you try to introduce new features or update some parts of the system. That is why, as a part of any modernization or changes, we typically conduct a complete code review, assessing the quality and “updateability” of the system’s source code.

  7. UI/UX Review
  8. The same principle applies to the UI and UX design. A thorough design review is required to understand which parts of the system interface need a “facelift.”

  9. Performance Testing
  10. Performance testing aims at uncovering further potential issues with the legacy systems. Poor performance or major flaws can serve as a reason for a complete system reengineering as well as selective improvements.

  11. Current Requirements and Opportunities for Future Growth
  12. While considering the current business needs and requirements articulated by the client, we also focus on opportunities for the future growth. Thus, we help you make an informed decision by providing a well-grounded and unbiased opinion on the software modernization options.

Legacy modernization methods:

The system evolves influenced by different development methods – from adding a line of code to complete reimplementation.

There are two methods for dealing with the legacy problem that involve major structural changes: revolutionary (big-bang) and evolutionary (band-aid). Yet, both have benefits as well as drawbacks.

  1. The revolutionary method revolves around developing and carrying out a legacy system replacement strategy. Its implementation requires shutting down the old system and building a new one from scratch. The approach might be considered extreme, but sometimes it is better to retire the system completely to avoid some serious damage, such as security breaches, lost data, system downtime. Or it can be applied in a case when the original product cannot solve the existing business problems anymore, so it makes no sense to reengineer or port it to the new technologies.
  2. The evolutionary method presupposes a systematic, step-by-step software modernization process. It is usually less painful: It does not disrupt the major business processes and implies significantly lower risks for the company. Yet, it often turns into a band-aid method, where you focus on solving the problems instead of removing the factors that cause them.
Approaches to legacy system modernization:

Below are three modernization approaches to help you pick the one that can deal best with your current legacy challenges.

While both Migration & Enhancements and Correction & Growth are drawn on the Evolutionary method, the third approach called Complete Software Reengineering takes a Revolutionary turn.

  1. Migration & Enhancements:
  2. This is one of the most popular approaches to application modernization and the easiest way to make sure your product will keep serving your needs for years to come. It presupposes the system migration (typically re-hosting, using cloud solutions) and some minor enhancements. This includes UI/UX updates, performance optimization, and database migration. Yet, this method has a number of limitations. Namely, the core business logic and architecture mostly remain unchanged, as this type of changes require a more invasive approach.

  3. Correction & Growth :
  4. If the product technology stack is relatively modern and does not represent a threat for future product growth, modernization can involve some minor enhancements/corrections. This might be architecture optimization or code refactoring, UX updates or performance optimization without significant changes in product business logic. As soon as the product is updated, you can add more features on top of it. These might be third-party integrations or custom-built modules.

  5. Complete Software Reengineering :
  6. Considered the most extreme approach, features extraction relies on your business strategy and growth outlook. This means, in order to reengineer the product, you need to identify the features that are still crucial to your business and the ones that are no longer used or required. After that, the required features are prioritized and modified if needed. Taking the legacy system as a basis, the team creates an up-to-date product with matching capabilities, but better performance, look and feel, modern technologies and scalable architecture. Depending on the functionality analysis and prioritization, the new product might 100% match the previous version in terms of functionality, or lack some features that are no longer required/used.

Legacy system modernization/ conversion techniques:

Legacy modernization approaches have specific techniques applied to update obsolete technologies.

  1. Encapsulation is a technique for reusing legacy software components. While leaving the code in its current environment, encapsulation connects it to the new presentation and accesses layers via an API. That helps leverage the application and extend its features and value.

    Encapsulation is based on the technology of wrapping that provides a new interface to a legacy component making it easily accessible to other software components. The little changes to the code minimize the risks. Consequently, encapsulation is among the fastest and most economical solutions. It is a good option when a legacy system has a high business value and good quality code. However, encapsulation will not solve problems already present, such as difficulties with maintenance and upgrading, since its main concern is the interface and not the internals of the legacy system.
  2. Rehosting means moving a mainframe application unchanged to other physical, virtual, or cloud infrastructure. This technique is of the lowest cost and risk. While re-engineering projects can take years, rehosting is faster and keeps the underlying business logic intact meaning zero negative impact on the enterprise. As a result, the system operates in exactly the same way.

    In terms of modernization, it makes sense migrating to modern open systems, like multi-tiered, SQL-based x86 environment, or the cloud. Migrating to x86 architecture systems result in lower purchase costs and have reduced space, power and cooling requirements. Cloud migration offers flexibility over on-site hardware in terms of resource scaling to match user demand. Aside from a cheaper upfront investment and no hardware outlays, operating through the cloud allows for more reliable data security, greater stability, and continuous updates. Cloud migration can be executed not only using rehosting, but also replatforming and refactoring techniques.

    With the rehosting technique, an application is forklifted to the cloud as is, without any code modification. While offering a less resource-intensive migration process, rehosting doesn’t generally make use of cloud-native features as do replatforming and refactoring techniques.

  3. Replatform migrations include a bit of up-versioning to adjust the code to a new platform while preserving existing functionality. The minimal changes like using a managed database offering or adding auto-scaling, a feature that automatically adds or removes compute resources, can help return the basic profit of cloud infrastructure. And that’s perfectly fine because not all applications need the full benefits of being cloud-native. In terms of cloud migration, replatforming allows for base cloud functionality and cost optimization, without resource commitments required for refactoring.
  4. Code refactoring presupposes restructuring and optimizing existing code without changing its external behavior. Refactoring an application component allows for solving technology problems and improving the component’s features and structure.

    By re-coding some portion of an existing application organizations are able to take full advantage of cloud-native features and maximize operational cost efficiency in the cloud. Meanwhile, there are certain technologies that are not runnable in the cloud. In this case you should look for a SaaS alternative.
  5. Rearchitecting means shifting to a new application architecture while altering the code to fully exploit the new and better capabilities of the platform. This technique has medium cost and risk, but also medium results.
  6. Rebuilding (Redesign) rewrites the application components from scratch while preserving their scope and specifications. At the same time, redesigning your application opens the door to new features, functionality, and processes that leverage the capabilities of modern technology and third-party platforms.
  7. Replacing. Sometimes it is better to entirely replace the app with a different tool rather than invest in its modernization. While the reuse of existing legacy business logic is not possible in this case, some level of reengineering or customization of packages and rewriting business logic may be involved in this process.

To sum up, modernization techniques impact different aspects of the legacy system. That said, encapsulation, rehosting, and replatforming affect the technology platform. Refactoring and rearchitecting can solve problems in the technology and architecture domains. Rebuilding and replacing allow for changing and adding functions and features, among other things.


Regardless of the chosen approach and technique, software modernization is a complex, labor intensive and risky process. Yet, the results are well-worth the risk.

Clarus will handle every aspect of legacy-system modernization: from analyzing the current solution, developing a solid business strategy, prioritizing the features to rebuilding your product from scratch, using latest technologies and architecture solutions

Reference Source:

“Legacy System Modernization: How to Transform the Enterprise for Digital Future”