Application modernization is the process of updating and optimizing existing software applications to improve their features, performance, security, and usability. This usually involves using newer technologies, methodologies, and architectures to bring the applications up-to-date.

There are several approaches to application modernization, including:

1. Rehosting: Also known as “lift and shift,” this approach involves moving an application to a new hosting environment, often a cloud-based platform. This method is typically faster and less disruptive than others, but it may not fully leverage the capabilities of the new environment.
2. Replatforming: This method involves making minor code adjustments to take advantage of new platform capabilities. It allows businesses to leverage the benefits of the cloud (like scalability and resilience) without rewriting the entire application.
3. Refactoring or Re-architecting: In this approach, you modify or rewrite the application code to move it to a new platform and take full advantage of its features. This is usually the most time-consuming approach, but it can offer the most substantial benefits in terms of performance, scalability, and cost-efficiency.
4. Rearchitecting: This involves a complete redesign of the application, often shifting towards a microservices architecture or serverless computing.
5. Replacing: In some cases, it might be more efficient to replace the legacy application with a new application. This approach typically requires adopting new software (SaaS solutions, for example) or writing a new application from scratch.
6. Retiring: If an application is no longer useful or cost-effective, it may be retired entirely. The data is archived and the resources are redirected elsewhere.

The specific strategy a company adopts for application modernization depends on factors such as the existing application architecture, business requirements, budget, timeline, and the company’s tolerance for risk and disruption.

Furthermore, application modernization not only allows organizations to leverage the benefits of modern technology but also to better align with modern practices such as Agile development, DevOps, continuous integration/continuous deployment (CI/CD), and others.

Modernizing an application can offer significant benefits, such as improved performance, increased scalability, better security, and cost savings. However, it’s a complex process that requires careful planning and execution. It’s often recommended to work with professionals who specialize in application modernization to ensure the project’s success.