What is a legacy system?

Legacy systems

A legacy system is an old or out-of-date system, technology or software application that continues to be used by an organization. Legacy systems no longer have support and maintenance but they can’t easily be replaced.

Systems tend to become obsolete over time. Businesses change constantly due to changes in the economy, new laws, market conditions, management, reorganizations, etc. All these changes often entail adaptations in the IT systems. Moreover, adaptations are usually implemented by many different people; which makes it difficult for IT managers to have a full view of the system.

IT managers must analyze which are their legacy systems and to which extent it is worth maintaining them. In general, legacy systems are critical to day-to-day operations, so their migration and replacement must be carefully assessed and planned to minimize potential risks.

Why are legacy systems still used? 

Reasons to maintain legacy systems vary among companies. Here are some of the reasons organizations keep using them:

  • They still fulfill a business need or are mission-critical systems.
  • It is an old technology investment that hasn’t been recovered yet. As IT systems are expensive, organizations need to use them for a certain period of time in order to make a profit of such investment. IT systems usually last for years but technology evolves at great speed.
  • Replacing a legacy system involves investing a quantity of resources — money, time and staff — the company can’t always assume.
  • The company lacks the IT skills to migrate the legacy system.
  • Organizations often lack the technical specifications to create a new system with the same features as the legacy system. This is often due to the fact that systems are usually modified by many people during their lifespan in order to adapt them to the specific needs of the business.
  • The organization doesn’t wish to replace it.

What are some of the most challenging aspects of going from a legacy system to a new one?

The replacement and migration of legacy systems is high in the list of critical elements within organizations. Replacing a legacy system is challenging, costly and time consuming. That is why it is essential to assess key aspects, such as: which is the legacy system condition, which are the business needs or which risks are acceptable.


Although maintaining a legacy system can become expensive in some cases, the costs of replacing it can also be high. It is important to assess and plan it properly for avoiding that the costs of the migration project rocket

For instance, the fact that certain business processes must usually be adapted to IT systems, in order to overcome the system’s flaws, can lead to important costs and unpredictable consequences.

Technical specifications

One of the main risks of replacing a legacy system is that the new system doesn’t meet the business needs. This is often due to a lack of technical specifications of the obsolete system. This can lead to mistakes or changes in the business rules that are specified in the software that can result in the loss of certain important data or functionalities.

In general, it is difficult to create a new system with the same features and functionalities as the legacy system. 

Data protection

Data protection is key; all data must be migrated properly to avoid data losses. So, make sure all data can be extracted securely, ensure compatibility between old and new formats and take the time to test and review the data.

User experience

Another challenge, which is often overlooked, is user experience. When planning a migration to a new system, all parties should feel involved to some degree. Some legacy users might be reluctant to change and considering their feedback can help you deploy a solution they feel more comfortable with.

Which are the main risks and issues of keeping a legacy system?

If legacy systems are critical for an organization, it is important to conduct security and performance audits once in a while. Because despite the numerous reasons to maintain a legacy system, there are also many potential risks and issues to consider. 

  • Compatibility. As they use outdated technologies, the legacy system can become incompatible with new systems or technologies that are also essential to your business. As a result, departments using legacy systems may not benefit from all the features other new systems offer.
  • Security. The lack of support, updates or maintenance, as well as the fact of using old security protocols and standards, leads to creating patches that can end up causing security breaches. This also makes meeting regulatory compliance more difficult.
  • Performance and productivity. Legacy systems become slower and slower over time, which means performance, efficiency and productivity can also decrease.
  • Maintenance costs and competitiveness. Maintaining a legacy system means investing money on an IT resource that will need to be replaced sooner or later.

Migrating legacy applications to the cloud

Migrating legacy systems and applications to the cloud is easier with a Private Cloud environment. Unlike most Public Cloud solutions, a Private Cloud allows more specific and custom configurations; making the migration easier and enabling legacy applications to run unmodified, if needed. 

By migrating your legacy applications from an on-premise data center to a Private Cloud, you will benefit from the scalability of cloud environments while maintaining custom-made configurations, and optimize costs. It is usually possible to deploy a virtualized environment that simulate the original environment for the most part. It is even possible to have extremely old operating systems (Windows XP, Windows 2000) and to move to a Private Cloud applications that need hardware keys — a method that was often used to validate the licenses of applications.

Legacy systems are often mission-critical for companies. Thus their migration must be properly assessed and planned.

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