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7 Options to Modernize Legacy Systems (ver 2)


Legacy systems have been an integral part of the IT infrastructure of organizations since the early days of computing. Over the years, however, the environment and usage of these systems have changed significantly. A large number of organizations still rely on these outdated and inefficient technologies. They no longer provide the necessary agility and scalability required in the digitally-driven business world of today.

Furthermore, the continuous emergence of disruptive technologies like the Internet of Things and AI, as well as business models such as the cloud and distributed ledger technology, require organizations to adapt in order to remain competitive. For many, this means modernizing their legacy systems, as these existing IT structures often lack the necessary scalability, safety, and data visualization capabilities.

This article explores and explains the seven options for legacy system modernization outlined by Gartner, Inc. – one of the world’s leading research and advisory companies – and examines how and when each should be implemented.

What are Legacy Systems?

Legacy systems are IT infrastructure that is more than three generations old and, as such, prone to failure. They frequently lack scalability. They are generally wasteful, and are not suitable for the modern digital world. Furthermore, legacy systems are often not secure enough and may not support vital technologies such as IoT and AI integration.

The advent and widespread adoption of cloud computing and distributed ledger technology has further exposed the shortcomings of legacy systems. These new technologies enable better data sharing and data visualization. Furthermore, the move towards digital transformation has pushed companies to move away from legacy systems and find alternative modern solutions.

Gartner’s Seven Options to Modernize Legacy Systems

In the face of rapid digital transformation and the emergence of cloud computing and distributed ledger technology, Gartner, Inc. has outlined seven options for legacy system modernization. These include:

  1. Rehost: This is the simplest and often cheapest option for legacy system modernization. It involves moving the existing system onto a newer, more cost-effective and better supported platform. This has the advantage of providing software and hardware support, as well as improved scalability.
  2. Replatform: This involves taking the existing system and migrating it onto a platform that can more easily integrate with other applications and data sources. This can often require significant re-engineering of the existing code and considerable investment in the new platform.
  3. Refactor: This option involves making incremental changes to the existing system in order to enhance its performance and scalability. Refactoring often requires a deep understanding of the underlying code and can be a time-consuming and costly process.
  4. Rebuild: This involves rebuilding the entire system from the ground up using the latest technologies and a library of reusable components. If the original system is too old or contains clunky or poorly written code, this is an excellent alternative.
  5. Retire: This option involves gradually phasing out the system and replacing it with a new technology. If at all possible, avoid using this option because it can be expensive and time-consuming.
  6. Replace: This involves completely replacing the existing system with a new technology. This can be done either by outsourcing the entire project or by buying a company-specific enterprise solution.
  • Retain: This is a hybrid approach that involves keeping the legacy system and augmenting it with newer technology. This can be an effective way to maintain existing systems while making them more efficient, secure, and up-to-date. It also allows organizations to reduce costs by retaining parts of their existing system.


Modernizing legacy systems is essential in today’s world of digital transformation and the emergence of disruptive technologies such as the Internet of Things and AI. Businesses that don’t update their outdated systems will fall behind as they attempt to compete in the digital era.

Gartner’s seven options outlined in this article provide a roadmap for these organizations, outlining when it makes sense to rehost, replatform, refactor, rebuild, retire, replace, or retain their existing systems. Before choosing, it is important to thoroughly weigh all seven possibilities because each organisation will have different needs and resources, which will determine which one is best.

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