4 Examples of Legacy Systems (And How to Modernize Them)


A legacy system is any outdated software or hardware that it’s still in use. Although the term may imply it, a legacy system isn’t necessarily an aged technology. It can be a system that lacks vendor support or doesn't meet an organization's evolving requirements. Or it can be a series of apps that still power critical internal workflows, often making businesses feel like they’re stuck in the past using an outdated platform that is disconnected from the modern, cloud-based ecosystem.

In this blog post, we’ll cover four examples of legacy systems that companies often struggle to modernize.

Why Do Companies Still Rely On Legacy Systems?

Most organizations keep their legacy systems because of at least one of the following reasons.

High migration costs

The IT system is running aging or end-of-life technology that may lack current documentation and be a labyrinth of add-ons and fixes. As a result, migration becomes complex and the resources needed to manage it come at a high cost.

Skills gap

The technology is supported by “mature” developers with hard-to-find skills. In the case of migration to another technology, organizations lack enough manpower to focus on the migration while keeping the business running as usual.


Legacy systems are often a mission-critical technology. Therefore, an organization can be fearful or concerned of the impact changing it or replacing it can have on the business such as downtime or lost business. 

4 Common Legacy Systems to Modernize

In a recent blog post, I looked at the three ways companies can modernize legacy applications by extending, refactoring, or rebuilding using a low-code application development platform. Now, let's look at some common legacy systems and explore how businesses have used low-code development to successfully modernize those systems.

There are many legacy systems out there, but there are four that are generally identified as the most common:

  1. SAP
  2. .NET and Oracle
  3. Lotus Notes and HCL Domino
  4. Sharepoint:

SAP: Unlock New Value with Low-Code

Organizations running SAP know that the customizations they’ve made to the core applications to meet the unique needs of the business can deliver value. However, the customizations can be expensive to build, and they often make it harder to upgrade and migrate to future versions of SAP.

Why extend your legacy SAP systems with web and mobile front-ends?

By extending your legacy SAP applications with a low-code application development platform, you can unlock new value with web and mobile front-ends without requiring scarce and costly SAP-specific development resources

Others take a different approach.

Modernize SAP in the cloud at your own pace

For some organizations, their legacy SAP systems aren’t just missing a few features or capabilities. They’re effectively hampering the innovation necessary to achieve or maintain competitive advantage.

A low-code application development platform can support cloud-based innovation that exists alongside the legacy systems of record, sharing data while providing new capabilities. Companies can modernize their systems at their own pace, and as each new component comes online, they can decommission the legacy applications until the transformation is complete.

.NET and Oracle: A New and Simplified Experience

Initially, homegrown core enterprise systems built in-house with technologies like .Net and Oracle have an advantage over COTS solutions by providing exactly the features the organization needs. But quickly, these systems run into similar issues as commercial systems: adding new features and capabilities to the core system is painfully slow and cumbersome.

Rebuilding the user experience, business logic, and data flows from the ground up as a homegrown cloud-native application might consume too much time, budget, and resources. However, building a new experience with a low-code platform can provide the flexibility needed to accelerate the development of needed features and capabilities and update them quickly.

Lotus Notes and HCL Domino: Replacing the Outdated

Lotus Notes is built on a 30-year-old+ architecture with a proprietary development framework, database, programming model, scripting language, and deployment methodology. Today, it lacks the security, flexibility, and agility that are now table stakes in modern applications.

Organizations are better off replacing their Lotus Notes applications using a visual, model-driven, and AI-based development environment to re-imagine the capabilities. You can create sophisticated and secure offline experiences that support everything from simple data caching to complex offline data access and synchronization.

SharePoint: Re-envision Collaboration

Like Lotus Notes, the legacy on-premises version of Microsoft SharePoint was once an innovative collaboration tool that is, by today’s standards, costly and complex to customize, difficult to scale, and lacks critical reporting and governance capabilities. Using a low code development platform, organizations can migrate from aging SharePoint applications and re-envision internal and external portal applications as optimized web and mobile apps.

Low-Code for the Legacy Modernization Win

Many organizations depend on legacy systems to support their core business processes. Low-code development offers an opportunity to bring them up to date quickly, without the risk and cost of traditional development.

With OutSystems, your IT team can quickly build intuitive apps on top of your legacy applications and make them available where employees need them most. With AI-powered visual development, out-of-the-box integrations, and world-class UI patterns and visual components, OutSystems empowers IT to easily extend, refactor, and rebuild existing systems for the future.

To learn more about how organizations around the world have easily and quickly modernized their legacy systems with OutSystems, download our new ebook, An IT Leader's Guide to Application Modernization.