When you begin to realize your home no longer suits your lifestyle, it doesn't necessarily mean you need to move. Usually there are some opportunities to upgrade and “optimize” your house to support the way you want to live. Today’s businesses and their legacy software are similar.


Over the past few years, due to a large event (which shall not be named) and some smaller ones, many organizations discovered their legacy systems needed an overhaul. Some applications have reached the end of support, creating unaddressed security, compliance, and other issues. Others are so outdated that it’s difficult to find people with the skills to maintain them. And most need a functionality overhaul to match what’s required to be a competitive, agile, and mobile-first organization.

At the same time, your legacy systems are still providing value (hopefully like your house). Many still perform the core functions they were designed for. Rather than consuming untold time and resources to rip and replace, it makes more sense to develop a modernization strategy that leverages their current value and may even extend their usefulness well into the future.

A healthy modernization strategy begins with deep discussion about what your business needs compared to your legacy systems’ current capabilities. If your core system delivers value but needs new access, integrations, or touchpoints, you can extend it with new capabilities.

If you have a number of systems that are not well integrated together, you can refactor them into individual microservices, one component at a time, as rapidly or gradually as necessary. And if your core, legacy-based system is truly at the end of its lifespan (or if your house can’t be fixed), you can rebuild it in parallel using the same data so that the switchover is as seamless as possible.

In most cases, the modernization process may be a combination of two or even all three of these approaches — some extension, some refactoring, and some rebuilding.

3 Legacy Application Modernization Options

Let’s look at each of these approaches to app modernization in more detail.

1. Extend to Unlock the Value of Your Existing Systems


Extending core systems is like upgrading the windows in your home: it provides a fresh view into your data. You should consider an “extend” approach to optimize and upgrade enterprise applications such as SAP with new user interfaces and front ends that tap into your current systems.

These can support new, customized processes and deliver updated user experiences via the web and mobile devices. You can even combine data from multiple systems of record or transfer data from one siloed system to another — all without affecting the base application.

You’re also avoiding the accumulation of technical debt that occurs every time you make customizations to legacy software, which can make updates increasingly difficult.

2. Refactor to Create a Flexible Foundation for Innovation


By decoupling the many components of your existing systems, you can refactor them to create a modular composite architecture that gives you the flexibility to innovate quickly and take advantage of cloud native technologies to drive innovation.

Like moving walls to create new rooms in a house remodel, consider refactoring when it makes sense to keep what you can of your legacy systems and modernize the rest over time. The advantage of refactoring is that it moves your systems toward an agile, cloud-centric microservices architecture by building new composable applications using bits and pieces of the old apps.

As is true with extension, you’re not disrupting the back-end system, but rather using an API approach to build new apps that bring the legacy data together in new ways to deliver new systems. Think of it as renovating a house one room at a time or knocking down a wall to combine two rooms into one. You can proceed at your own pace until you’ve made all the upgrades you need.

3. Rebuild Your Core Systems with a Modern Platform


If a system is truly past its sell-by date, you may seriously consider starting over. (We’re looking at you, Lotus Notes!) Consider rebuilding a core system when the cost to fix the technical debt exceeds the cost to start from scratch.

This could be an enormous undertaking, requiring complex data mapping and migrations, but it doesn’t have to be. By employing the same hands-off techniques as you would to extend or refactor, you can build a fully functional application alongside your existing systems that pulls from the same data.

Once the new system is ready, the transition can be seamless. It’s important to note that rebuilding should also mean re-envisioning and building better, incorporating the streamlined business processes, automation, flexibility, and mobility a modern organization requires.

Legacy Application Modernization with Low-Code

Modernizing your legacy systems doesn’t have to be a painful or difficult process. Our eBook, How to Unlock the Power of Your Existing IT Systems, provides a deeper look at how a low-code development platform like OutSystems lets you modernize at your own pace using these three approaches, including real-world examples of modernization strategies in practice.

Download How to Unlock the Power of Your Existing IT Systems to start your modernization transformation today.