Published Date: October 17, 2022
Application and IT modernization is the process of adapting or upgrading legacy software and the IT infrastructure that supports it. A legacy system or application, according to Gartner, is “an information system that may be based on outdated technologies, but is critical to day-to-day operations.” Specific actions taken during the application and IT modernization process vary depending on an organization’s size, industry, budget and other factors. However, modernization generally involves moving away from old solutions and adopting new technologies, consolidating systems and workflows, and implementing automation to streamline business operations..
Application and IT modernization is necessary for organizations to meet rapidly changing business demands. Monolithic applications developed and maintained using waterfall application development processes and deployed on on-premises IT infrastructure don’t provide the flexibility and scalability businesses need to thrive in a competitive marketplace. Application and IT modernization is a way to refresh outdated applications and let them take advantage of newer technologies and computing approaches. With it, developers can overcome their legacy applications’ architectural restrictions and retool them for cloud architecture and continuous delivery and deployment patterns.
Application and IT modernization is a critical feature of an organization’s overall digital transformation strategy. In the following sections, we’ll explain different application modernization strategy approaches, why it’s an important strategy for every organization, and the advantages and challenges you can expect when undertaking your own modernization. We’ll also provide some best practices for getting started.
What does application modernization mean?
Application modernization refers to the practice of updating older applications to take advantage of new computing approaches. Maintaining legacy applications can be resource-intensive and costly, especially as organizations adopt digital infrastructure. Rather than retire or replace applications that are often among an organization’s most mission-critical, the organization can modernize — and optimize — them to extend their lifespan and create new business value from them.
In this way, application modernization lets an organization refresh its application portfolio, including critical applications, to take advantage of new programming languages, frameworks, infrastructure platforms and other technological evolutions. An effective modernization strategy can increase the frequency and reliability of new feature deployments, improve uptime and resilience and lower the costs of running the application for peak operational efficiency. Application modernization is a component process of cloud modernization, an umbrella term for updating an organization’s IT infrastructure and processes to take advantage of digital technologies such as public clouds (such as Google Cloud or AWS), machine learning, automation, remote collaboration and communication platforms, and mobile and IoT devices.
There are several approaches to modernizing an application. The various options offered by application modernization services include:
- Rehost: Commonly referred to as “lift-and-shift,” rehosting takes an existing application and moves it “as is” from legacy infrastructure, such as an on-prem server or mainframe, to more modern infrastructure, such as a public cloud platform. Rehosting is generally the quickest and least labor-intensive approach because there are few changes to the application’s code or architecture — you’re replicating the application in the target environment without making any changes to its functionality. And the cloud provider manages most of the underlying infrastructure once the shift is complete. However, rehosting can erode cost savings in the long run because lifted and shifted applications typically aren’t cloud-optimized, which can result in degraded performance, overprovisioning compute resources and observability issues.
- Refactor: Refactoring refers to rewriting, restructuring or repackaging application code. This strategy involves taking a legacy application and revising chunks of its underlying code so it runs better in a new environment, typically a cloud infrastructure. Refactoring allows developers to connect an existing application to cloud-native infrastructure and tools such as containers, databases and identity management systems with minor code or configuration changes.
- Rearchitect: This modernization approach involves modifying or extending an existing application’s codebase to give the app a modular architecture for better scalability and reliability in the cloud. Because it involves significant code changes, it’s the most time-consuming way to migrate an app to the cloud. A common example of rearchitecting is decomposing a monolithic application into microservices.
- Rebuild: This approach involves redeveloping an existing application on a PaaS (Platform as a Service) or IaaS (Infrastructure as a Service) architecture in order to deploy it using modern cloud services. Rebuilding is different from rearchitecting because rebuilding requires complete redevelopment of the application whereas rearchitecting only modifies parts of the app. Rebuilding an app is costly, but the resulting cloud-native application is inexpensive to use and highly scalable.
- Replace: Replacing involves discarding an existing application and replacing it with SaaS. Because the underlying infrastructure, app software and app data are managed by the service provider, this is the best option for organizations looking to save on IT development costs.
- Replatform: The replatforming modernization approach strikes a balance between rehosting and refactoring. Changes are made to specific app components, such as modifying or replacing the application’s backend database, to enable the legacy app to function better in a cloud environment. Replatforming allows organizations to add new features or improve scalability, security, or user experience while avoiding the expense and downtime of a full rearchitect overhaul.
Each application is unique; its requirements will vary based on the application architecture and its deployment, function, user experience, lifecycle and other factors. Application modernization approaches should be weighed against their difficulty, cost and overall value.

There are six main ways to modernize an application that aim to take advantage of digital technologies such as public clouds, machine learning and automation, among others.
Why is application modernization important?
Application modernization is important because legacy applications — despite the negative connotations — often represent an organization’s most mission-critical software. Most organizations aren’t willing or able to simply retire or replace their legacy apps as the resource and downtime costs of starting over from scratch are too great. Application modernization lets them protect their application portfolio investments and create new value from it by enabling legacy apps to take advantage of new architectures, platforms, tools and other technologies.
It’s also increasingly difficult to hire people who know how to work on non-cloud infrastructure. These days, qualifications for new talent will include cloud experience, with the expectation that their apps will all operate in the cloud.
What is an example of application modernization?
Monolithic architecture is the traditional software model. Monolithic applications contain all their functionalities within a very small number of applications, which makes them easy to develop, deploy and debug. However, as these applications get larger, so do their start-up and deployment times. They also require redeployment of the entire app for even small changes. Because the functions of the application aren’t split, a single bug in any module can cause the entire monolithic application to fail. This same constraint makes monolithic applications extremely difficult to use with cloud technologies.
Because of these disadvantages, progressive organizations commonly use a rearchitecting approach to decompose their monolithic application into microservices. This allows them to decouple the application’s components into separate, independently deployable and scalable applications. Ultimately, this results in increased deployment speed, more flexible scaling, reduced costs and higher application performance.
What are the main benefits of application modernization?
Application modernization offers several benefits, including:
- New features and services: Application modernization empowers businesses to develop new features and services that align with current needs and goals. For example, breaking up a monolithic application into microservices can accelerate the development speed and deployment cadence for each of the new microservices, while leaving core business logic intact.
- Increased productivity: Sluggish legacy systems and applications that don’t perform as they should will frustrate users and hamper their productivity. Training every new hire on how to use inefficient legacy IT systems is an additional time waster. Application modernization solves both of these problems by providing employees with reliable modern tools that will increase their productivity and work satisfaction.
- Reduces technical debt: Organizations incur technical debt the longer they continue to maintain legacy applications past their point of usefulness. No amount of patching and bug fixing will salvage a system that no longer meets business and customer needs. Modernization greatly reduces technical debt without the organization having to purchase completely new systems. Modernization also reduces operational costs as organizations don’t have to spend as much to maintain outdated code and resolve performance problems.
- Improved customer experience: Customers expect fast, modern applications and services. An outdated or poorly performing legacy app can be the difference between earning their return business or driving them to a competitor. Application modernization can enhance the customer experience through simple changes, such as upgrading a user interface, adding new features or automating manual processes.
- Enhanced security: Because of their reliance on legacy software and accrual of vulnerabilities over time, legacy apps pose a significant security issue for many organizations. The longer an app has been around, the more time hackers have had to study and exploit its weaknesses. Modernizing legacy apps provides an opportunity to shore up any structural weaknesses, and once deployed to the cloud, the app can take advantage of its robust modern security features.
- Increased revenue: Modernized apps are simply more flexible than legacy apps, allowing organizations to more easily create additional customer value through new features, functions and services. The net improvements these bring to customer experience drive return business and customer recommendations that translate into more revenue.
What are the challenges of application modernization?
Some application modernization challenges that organizations may face include:
- Legacy application dependencies: Legacy applications and components such as network configurations, data, and security are tightly coupled with the underlying infrastructure. This makes it challenging to upgrade the application and can require enormous time and effort.
- Knowledge and skills gaps: The sheer age of most legacy software means that there are likely few developers within the organization that understand the application technology stack. This makes it difficult to analyze the app for the required application modernization needs. Additionally, legacy application source code has often been developed and patched over years without documentation, requiring developers to manually review and test the code. This is a Herculean task that requires time, resources, knowledge and skills that many organizations have in short supply.
- Maintaining uptime: Many organizations are dependent on their legacy software for critical business operations. Large legacy apps may take a significant amount of time to modernize and any hiccups along the way can result in unexpected downtime. The organization’s needs and compliance requirements may also shift along the way, possibly necessitating extra time to adapt the modernization process to these changes. Developers must manage the modernization to ensure it doesn’t disrupt the organization’s business operations.
- Time and cost: Application modernization is time-consuming and costly, although less so than scrapping old software and building new apps from scratch. Still, it’s important for organizations to find skilled, experienced developers who understand their business and can adapt to changes quickly to minimize costs.
- Resistance: During the application modernization process, organizations may face resistance from employees who are reluctant to embrace new technology and processes. The organization must convey the importance of application modernization for the business’s growth and development. The sooner employees buy into the modernization initiative, the easier it will be to foster their collaboration with developers and ensure there are no roadblocks to updating the applications
How do you get started with application and IT modernization?
To get started with application and IT modernization, first evaluate your most critical legacy apps and identify pain points. These could be performance problems, security vulnerabilities or other issues. Once you’ve identified pain points, consider how you can create new value through enhancements or new features, and which approach to modernizing your application is best for you.
Rather than tackling all your high-value legacy apps at once, start by solving a single problem to demonstrate the value of modernizing legacy applications and garner internal support. With a win under your belt, it will be easier to expand your modernization efforts to other parts of the organization.
What are some important components of application modernization?
Some important components of application modernization include:
- The cloud: Application modernization is all about taking advantage of the efficiencies of the cloud through cloud computing. Most people think of the public cloud in this context. However, private, hybrid cloud, and multicloud strategies are equally important. Some organizations may not be comfortable or ready to migrate directly from on-premises data centers to a public cloud because of security concerns, architectural restrictions or myriad other reasons. The other cloud models allow organizations to develop modernization — and relevant cloud migration — strategies based on their particular needs and concerns.
- Serverless: Serverless, short for serverless computing, is a model where third-party cloud providers host an organization’s software applications and dynamically allocate the resources to run them. This relieves the organization’s developers of having to manage their own physical or virtual machines (vms), operating system, networking and other infrastructure components required for the application to run and lets them focus on improving their applications.
- Containers: Software containers allow developers to package an application's code, configuration files, libraries, system tools and everything else needed to execute the app into a self-sufficient unit that can be moved and run in any environment. Containers can be managed and scaled with a container orchestration tool such as the open-source system Kubernetes, and they enable the creation of microservices, which break applications down into single-function modules that are accessed only when they’re needed. This enables developers to modify and redeploy a particular service rather than the whole application.
What are some steps for modernizing an application?
The following would be typical steps for creating a comprehensive roadmap for modernizing an application:
- Decompose the monolith: Monolithic applications contain all their functionalities within a tightly-coupled small number of binaries, so the first step is to deconstruct the app into its various functionalities. Decomposing the monolith into its working parts will make it easier to create a virtualized environment and help determine what microservices are needed to replace each area of functionality.
- Decouple the application from infrastructure: Monolithic apps’ data, networking and security configurations are tightly coupled with the underlying infrastructure, making it difficult to upgrade individual components. To modernize these apps, you must abstract their functions into independent components that allow you to migrate the app among cloud environments, servers, container tools and so on, without having to rewrite any code. For a variety of reasons, portability is important to consider when doing this work.
- Catalog app components: Once the application is deconstructed, you can maintain a catalog of its functional components that allows you to split the app into microservices. This lets DevOps teams choose combinations of components as needed and clone complex environments for testing and deployment in just minutes. Cataloging the app’s components also speeds up nearly every process from performance testing to migration
- Build in security: Security should be treated like any other application component and built in from the beginning. This will smooth continuous delivery processes and ensure the app is protected as soon as it's deployed.
- Integrate with DevOps: Integrating the application with continuous deployment tools and business processes such as DevOps will make it much easier to perform future upgrades. You should also enable the app to be provisioned on demand by connecting it with the orchestration tools you are currently using to provision infrastructure.

A comprehensive roadmap for modernizing an application includes decomposing the monolith, decoupling the app, cataloging components, building in security and integrating with DevOps.
The Bottom Line: Application and IT modernization is the key to unlocking your digital transformation
Applications are the pillars of successful businesses. Organizations can’t afford to be shackled by plodding performance and outdated interfaces. Application modernization gives new life to your legacy applications and ensures they can support your business needs for years to come.

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