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Legacy system application migration is the process of migrating existing systems or applications from outdated platforms to a more modern environment.


Legacy System Application Migration: Benefits, Challenges, and Best Practices

Posted by Angela Davis on June 29, 2023
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Legacy system application migration can help businesses that are currently struggling with using legacy systems. 

Legacy system applications are built with older program languages, for example, COBOL or RPG, but are still used to run critical business operations. As companies can become very dependent on these essential apps, they are difficult to replace, even if they no longer meet customer or business needs. 

The good news is that legacy applications can be transferred to modern platforms, which have the necessary resources to improve efficiency and enhance user experience. This process is known as legacy system application migration. 

However, while migration can help businesses improve customer experience, adapt to new technologies, and tackle industry challenges, it is only one of the paths to digital modernization and is not a one size fits all approach.

Depending on your business needs, a hybrid integration strategy, which allows you to continue using critical capabilities and benefit from cloud services without committing to a full migration, may be a better choice.

A thorough understanding of legacy system application migration will help you identify the best modernization method for your business.


Why migrate legacy applications?

Legacy system applications can sabotage business growth potential and pose risks to productivity, adaptability, and security. Over 44% of CIOs (chief information officers) claim legacy systems are responsible for slowing down business growth.

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Businesses often use these applications for many years before recognizing the dangers and modernizing to newer technologies. It could be a legacy core system (transaction servers such as Mainframe or IBM i / AS400), ERP (enterprise resource planning) system, CRM (customer relationship management) software, or accounting program that’s the problem.

Regardless of type, migrating your legacy applications to newer platforms breathes new life into your business, whereas maintaining outdated software means wasting resources on things like upgrades to fix compatibility problems.

These issues can increase costs and put your business at a disadvantage relative to competitors, ultimately stopping you from reaching your full potential. That’s why it’s crucial that businesses prioritize legacy migration. 

Organizations using legacy systems need to consider the fluid nature of consumer behavior and adopt efficient systems and technology as business dynamics continue to evolve.

The key advantages of legacy system application migration are improved system performance, enhanced security and compliance, and reduced business expenditure.

Improved system performance

Aging legacy systems can damage efficiency and productivity. By investing in legacy application migration, however, businesses can leverage cutting-edge software and technology, boosting processing speeds and overall system performance.

Enhanced security and compliance

Legacy systems often no longer have developer support or up-to-date security measures, leaving them at greater risk of cyberattacks and security threats. By moving to a modern system, businesses can take advantage of stronger security protocols and features to safeguard their data and applications.

Reduced business expenditure 

Older systems can be costly due to the complexity and specialized knowledge (such as COBOL) required to keep them operational. By moving to a newer platform, businesses can utilize new development tools and processes, streamline IT infrastructure, and prioritize other pressing business needs.

In addition to the above benefits, migrating legacy software can also help you achieve the following for your business:

  • Seamless integration. A modern platform supports seamless integration for business applications, helping you streamline workflows and foster better collaboration between departments. 
  • Exciting new features and better functionality. Migrating legacy systems often means gaining access to exciting features, which can boost functionality. This helps businesses thrive in competitive marketplaces and adapt to changing business needs.
  • Better scalability. Legacy systems may struggle to accommodate the workload as your business expands over time. Modern environments offer scalable technologies, such as cloud-based services that support expansion and sustained growth. 
  • A memorable user experience. New features and functionality provide a more rewarding user experience, which can significantly improve your productivity levels. 

Overall, legacy system application migration helps organizations stay ahead of the competition and reduces the burden of maintaining outdated systems.

The main challenges of a legacy application migration to the cloud

There are several steps involved in a successful migration. These should include an examination of your existing system, the creation of a migration strategy, testing of the new environment, and user training. Application code and data structures may also need updating for full compliance with the modern platform.

Compatibility is often the biggest challenge in legacy system application migration. To get the new system working smoothly, you must prepare for the migration project and conduct extensive testing before deploying it.

Despite the challenges involved, the strategy of migration for legacy system modernization continues to gain popularity. Projections claim that by 2025, the global application modernization market will reach $24.8 billion (at a CAGR of 16.8% from 2020). 

AttractiveOpportunities in the Application Modernization Market

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Application migration frameworks and automated code conversion tools are two examples of resources that can help with migrating legacy applications. 

Here are some of the main legacy system migration challenges to watch out for:

Technical challenges

Increasing the reliability and performance of your applications should be one of the main aims when you decide to upgrade to a modern environment. Keep in mind, though, that legacy software can be bulky. As a result, it's likely that you'll lose certain features and functions that previously influenced the performance of the application.

Some legacy applications may also be incompatible with modern cloud servers since they were developed using outdated technologies. Significant changes to the application's code are one solution to such cases, however, this can make the process longer and more expensive.

Another solution for systems or applications that cannot be migrated is hybrid integration. This method connects on-premises infrastructure with cloud-based services, allowing businesses to maintain existing critical capabilities while selectively adopting cloud-native services for their benefits. 

Hybrid integration acts as a catalyst for digital transformation and is an alternative to complete migration. As a modernization strategy, it allows companies to preserve valuable investments, critical functionalities, hard-to-access data, and essential processes while leveraging the scalability, flexibility, and cost-efficiency offered by the cloud.

Risks of project delays and cost overruns

Legacy modernization projects can be a handful. You might need to transfer large data volumes found in legacy systems to the cloud. Data migration in such cases is a challenging procedure that has to be well-planned to avoid data loss or corruption.

Besides this, you might also have financial limitations that require close attention, since uncertainty about the migration project's scope early on and inaccurate budgeting can lead to cost overruns later on.

In reality, you might need to spend more than initially allotted. So, you need to leave room in your budget for any additional, unexpected expenses that may arise as you attempt to resolve issues, transition to modern technology, or scale your teams.

Security and compliance risks

It’s possible that your legacy programs were built with outdated security features and haven’t been upgraded to account for modern threats. Moving these applications to the cloud can actually increase the likelihood of security issues, cyberattacks, or data leaks.

It might also be difficult to get the necessary in-house expertise to configure cloud infrastructures for older applications. Vulnerabilities and compliance issues might occur if the system isn’t properly set up.

It's also important to remember that there are some security concerns unique to the cloud that may not be present in legacy systems. 

That said, the risks associated with transferring legacy apps to the cloud can be managed with proper planning and the assistance of cloud service providers with experience in this area. 

It’s essential to conduct in-depth security and compliance evaluations before and after the transfer to locate any weak points and guarantee that the application complies with all applicable industry standards.

Innovative solutions for legacy system application migration

While it's true that moving legacy applications to the cloud can be tricky, keeping them has several hidden costs.


Hidden Costs of Legacy Software

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The benefits far outweigh the challenges. Better still, there are several innovative tools available to make the transition smoother and ensure as little downtime as possible. 

The best way to identify the correct approach for your business is to see which fits your organization’s requirements.

Here are some innovative solutions for legacy system application migration. 


Rehosting, commonly known as "lift and shift," is a method for legacy application migration to the cloud that doesn’t involve modifications to the source code or underlying architecture of the program. 

Although this is a cost-effective approach for migrating legacy applications to cloud environments, it is not the best option for every application.

Using a rehosting strategy means creating a virtual machine or container with the necessary software to operate the legacy application in the cloud, including the database, middleware, and operating system. This method is typically employed for migrating large-scale applications used in accomplishing critical business objectives, such as a rapid product rollout or vacating a physical data center.

Here are some benefits of rehosting:

  • Cost-effective. Rehosting can save you money by allowing you to move your legacy apps to the cloud with few modifications to their code or architecture.
  • Migration speed. As rehosting doesn't require major changes to the source code of the targeted apps, it's a good option for swift migration to the cloud.
  • Low risk. Since the application isn’t changed during the rehosting process, the associated risk is low. Errors and service interruptions can be avoided as a result.
  • Improved performance. When rehosted in a cloud environment designed for scalability and performance, the performance of legacy applications can be significantly enhanced.
  • Better security. Rehosting legacy applications in secure cloud environments that are built to prevent cyber attacks and data breaches is an excellent way to boost security.

However, rehosting is not without potential drawbacks. Due to the lack of changes made to applications during migration, they may not perform as well as they could  in the cloud. The challenges of integrating legacy applications with cutting-edge cloud services may also remain.

This might cause problems with performance or prevent you from benefitting from cloud-native tools and services. To guarantee that the rehosted application continues to function properly in the cloud, it may also still need regular maintenance and management.

Organizations that need to transfer legacy applications to the cloud quickly and affordably may find rehosting a useful alternative; nevertheless, before moving forward with your migration, it’s crucial to carefully weigh the benefits and downsides of this approach.


Refactoring involves making changes to the app's code and architecture to migrate legacy system applications to the cloud. This method allows businesses to restructure their applications for optimal performance and make full use of the flexibility, scalability, and cost-saving features of cloud services.


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Here are some of the key benefits of refactoring for legacy system application migration:

  • Better performance and scalability. Refactoring helps businesses rebuild their applications to take advantage of cloud-native capabilities and services, which improves both performance and scalability.
  • More flexibility. Legacy applications can be made more flexible and adaptive by refactoring since this involves splitting them into smaller, modular components that can be upgraded or modified as needed.
  • Better security and compliance. By adopting industry-standard cloud security and compliance policies, refactoring can help businesses boost app security.
  • Improved user experience. Refactoring can enhance the user experience by making applications more user-friendly and improving responsiveness.

There are several challenges to consider before choosing a refactoring approach. If the application's code is particularly complicated or poorly documented, refactoring can take a long time and cost more. Furthermore, this method can be a high-risk— if not conducted correctly, refactoring operations can lead to significant downtime or data loss.

That said, refactoring is a great choice for businesses that want to leverage the full power of cloud-based services and are in a position to dedicate the necessary time and resources to modifying their applications. 

More tips for a successful legacy application migration

There are several reasons why legacy application migrations fail. Many businesses don't notice the risks until they're well into the move and the system's performance is already suffering. 

The reputation, productivity, and revenue streams of your business are all at risk if your migration fails. Luckily, paying attention to these crucial tips can help you avoid such a situation.

Conduct a thorough analysis of existing applications

Successful legacy application migration requires careful analysis of the current application landscape. You must assess all your apps to see which ones need to be transferred.

This process should include finding out what makes up an application, how it works, and what its performance and scalability needs are. After doing this, you can better anticipate and prepare for any problems that could arise during the migration process.

Determine if the apps' supporting infrastructure can be moved to the cloud, and then create a migration strategy complete with resources, timelines, and budgets. Risk analysis and backup plans should be put in place to tackle any problems that arise during the migration.

Choose the right migration strategy and technology

Determine if rehosting, refactoring, or a hybrid of the two is the best migration strategy based on your examination of the existing applications. Each approach has its pros and cons, so your choice needs to depend on the complexity of your application, your business needs, and the timeframe available to you for your migration.

Explore the cloud service options available to you, and select the one that best serves your business. This involves thinking about things like security, scalability, and price.

Develop a comprehensive testing plan

Do a practice migration to ensure a smooth transition when it’s time for the real deal. During a test migration, you can run the app in a setting that closely mimics real-world situations.

The purpose of the test is to eliminate any bugs in the system and gain insight into how users will engage with the new environment before the full rollout. These tests can be time-consuming, as they require users to evaluate the application in real-world scenarios. Despite the time commitment, however, this remains a low-risk strategy for finding problems ahead of time.

When the migration is complete, test the application extensively to confirm it’s performing as expected and continues to fulfill the needs of the company. Make sure the app is always optimized for the best possible performance in the cloud.

Migration from your legacy applications is the future of your business

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If you want to keep up with the competition in today's dynamic market, you need to migrate away from outdated legacy systems.

Legacy applications have a reputation for being inflexible and can limit the growth potential of your business. Legacy system application migration, however, can propel businesses to greater heights and help them modernize their operations to satisfy customers.

How can OpenLegacy help your legacy system application migration?

OpenLegacy can help your business complete legacy system application migration your way. OpenLegacy Hub can directly integrate on-prem services with target cloud environments. We can even integrate monolithic, homegrown, or complex core applications. 

By matching application architecture, OpenLegacy’s unintrusive, core-to-cloud approach enables flat, de-layered integration, enabling swift completion of your modernization project while reducing costs and risks.

Contact us to request a demo today!



FAQS about legacy system application migrations 

How do I migrate legacy systems?

  • Determine what information will be transferred to the new platform.
  • Find out the money, time, and resources you'll need to migrate.
  • Conduct a data backup.
  • Develop a migration strategy for your system.
  • Test the migration plan.
  • Conduct routine maintenance checks.

Ultimately, it’s important to plan, execute, and manage the migration of old systems carefully. Collaboration between business executives, IT teams, and end-users is crucial for a smooth transfer that benefits all parties involved.

What is a legacy system conversion?

The term "legacy system conversion" refers to the process of converting an older system into a new platform that accommodates modern technological features and standards. Existing software, processes, and data repositories must be modified to run on the new system or platform.

Several stages, such as code translation, data mapping, and testing, may be necessary to guarantee that the converted system is up to par with all specifications and performs as intended.

Some of the reasons for converting legacy systems include making them more efficient, cutting down on maintenance costs, and allowing them to be integrated with newer software and hardware. 

Businesses can improve their IT infrastructure, increase application longevity, and reduce operational disruptions by modernizing their outdated systems.

What are examples of legacy applications?

Legacy applications are crucial to business operations but were built using outdated technology. Mainframe software is one such example. These centralized, enterprise-level systems were designed to handle vast volumes of data and first emerged in the 1960s and 1970s. 

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