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legacy application modernization
2020-05-22 /

How to Modernize Legacy Applications

Legacy applications are software apps that are older than the current technology.  When these applications become outdated, there are three ways to go: discard, replace, or legacy application modernization. But how do you modernize legacy systems? 

Some entrepreneurs are having a hard time dealing with their legacy applications. Back then, these applications were the engine of every company’s operations since they are created for specific and immediate use. 

However, technology is rapidly changing for the better. With each passing time, these applications might eventually become incompatible with emerging systems and platforms that, in turn, can ruin your business.

So, here’s the nagging question in the back of our minds; what is modernizing legacy applications?

What are Legacy Apps, and Why do they Still Exist?

Legacy applications are outdated or obsolete software programs. These are essentially software systems that function as a core business process within the company. However, newer technologies are superseding legacy systems. Instead of helping the business grow bigger and better, legacy apps are now becoming more of a hindrance.

For businesses, there are two types of legacy applications. One of those are apps that perform critical operations that can paralyze or even destroy businesses if left outdated. The second type is those that despite their age, are still useful these days.

For the first type of legacy app, there is really no great need to replace your entire system. That is why there is what we call application modernization. 

To qualify for modernization, these are the four most common criteria:

  • the system can no longer receive support and maintenance
  • they are mostly incompatible with modern or more advanced solutions since they are based on outdated technology
  • these applications are no longer available for purchase
  • causes bottlenecks in the entire business process

If your current system falls under these criteria, your system needs legacy application modernization.

legacy applications

If legacy apps are such a hindrance to a company’s growth, why do you think they still exist? There is one answer to that question: they are hard to replace since the essential business processes are dependent on these applications.

Changing to a modern system is such a high risk for companies. When businesses decide to discard an application used for years, the company needs to manually transfer or migrate decades of data. This process can lead to many risky outcomes, and one of which is data security. Switching to a more advanced system can corrupt essential data. If worse comes to worst, the data could leak to the public or gone for good.

Though changing from legacy systems can pose a considerable risk, they should not be kept indefinitely. But, instead of replacing them, why not modernize these applications? Choosing whether to discard, replace, or modernize your system is a hard decision. So, you need to have a legacy modernization strategy.

Benefits of Application Modernization

Why modernize legacy applications? Maybe some businesses do not find legacy applications as worrisome as most, but application modernization has a lot of benefits that it seems.

Adapt to future demands

Legacy apps are being left behind by a lot of modern systems. Compatibility is one of the banes of old systems that a lot of businesses are currently facing. Even though your application is currently running as is supposed to, you should also think way ahead just as an entrepreneur should. By modernizing legacy applications, you can adapt to the future demand of the technology and the industry.

Increase productivity

By modernizing your legacy application, there will surely be a decrease in application incidents. Modern systems are easy to diagnose and can receive support and maintenance. Legacy applications have a lot of technical limitations that can slow down your staff productivity. 

Improve business reputation

Once you modernize your current legacy apps, you increase your productivity and improve the quality of your products and services. With that, you are also improving your business reputation. An increase of excellent reputation also maximizes the return of investment (ROI).

6 Strategies for Application Modernization

There are different forms of application modernization, but it boils down to one common goal. Modernization is about modernizing the legacy application’s structure to make it up to date.

Modernization includes moving data from a legacy data center, moving data into the cloud, updating legacy applications, and refactoring monolith applications into microservices.

Some applications are relatively hard to modernize. Take, for example, applications such as SAP, Oracle, or PeopleSoft. These applications are often designed as individual, unbreakable monoliths. The process of modernization with these applications could take weeks, long enough time to affect your business. So, how to modernize legacy applications such as these?

Learn How to Build and Scale Your Business

To overcome this dilemma and other legacy application challenges, this article presents ideas on ways that could help you modernize your legacy applications. The list consists of seven processes divided into three categories:

Low-risk process

  • Encapsulation
  • Rehosting
  • Replatforming

Medium risk process

  • Refactoring
  • Rearchitecting

High-risk process

  • Rebuilding
  • Replacing


Encapsulation is one of the quickest and most economical processes of modernizing legacy applications. This process requires leaving the application code in its current environment and subsequently connecting it to the new presentation and access layers. Along the process, there may be a need to reengineer interfaces, but changes in the code are very minimal. With very little change, encapsulation provides a few risks and the cheapest modernization process.

Though highly accessible and low-risk, encapsulation does not address other current legacy application problems, such as difficulties in maintenance and upgrades. This process is merely focused on the interface.


Rehosting is one of the most effective strategies for application migration. This process is often called “lift and shift.” How so? The rehosting process involves lift, which is the moving of critical and core applications from the mainframe. Then the applications go shift, referring to migrating these applications to contemporary hardware or in the cloud.

Similar to encapsulation, rehosting also requires minimal code changes, so it is also cost-effective and low risk. Mainframe applications are recompiled in an open system like SQL-based x86 environment or cloud without a major change to the business logic.


If rehosting has the process nickname of “lift and shift,” replatform migration strategy has “lift, tinker, and shift.” The two processes are somewhat the same except for the “tinkering.”

The first process is still lifting the application from the mainframe. However, instead of directly migrating to a modern to the cloud or other modern system, the portion of the application (or the entire application) must first be optimized.

By optimizing the application before migration, you reduce a significant amount of time. This approach also allows developers to reuse resources they are accustomed to, such as legacy programming languages, existing caches in applications, and development frameworks.


Unlike before mentioned processes that leave out significant code modification, refactoring requires major changes in the application configuration. It is now a bit more complex since the process makes application code changes, yet ensuring that it does not make any impact on the application’s external behavior.

If your organization’s existing legacy application resource is intensive, then this can cause more massive cloud billing. Before the application is moved to the cloud, it needs re-coding some portion of your existing application for better resource utilization.


Rearchitecting a new application entails average cost and medium risk in modernizing your legacy application. The process description is simple, but the process is quite complicated.

To rearchitect an application that is between five to twenty years old, the application code is altered to enable the shift to new application architecture. In this way, you can fully take advantage of the current and better capabilities of the application platform.


Rebuilding is a high-risk modernization process that can lead to a lot of pitfalls if not done right. By rebuilding an application, you rewrite the app’s components from scratch while at the same time preserving the scope and specifications.

Though high on risk, rebuilding opens new doors to newer features, processes, and functionalities that your organization uses to leverage the capabilities of modern technology and third-party platforms.

Application Modernization with Full Scale

Since technology is rapidly changing, a lot of legacy applications are holding back businesses from growing. Businesses need to adapt to dynamic demands and find cost-efficient methods and resources.

In Full Scale, we acknowledge that legacy applications are every software developer’s greatest enemy. However, we have experts in legacy application modernization, project management, and data integration to help you address legacy issues and critical core business processes strategically. 
Don’t let your many-year-old software system hold your business back from growing. If you are in doubt whether your legacy application should grow or go, then contact us at Full Scale to schedule a FREE consultation.

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