A Comprehensive Guide to Angular Migration: Benefits and Best Practices

The 2024 Stack Overflow Developer Survey highlights Angular as one of the top three front-end frameworks, boasting a 17.1% usage share. The framework is known for its versatility, wide range of UI/UX design capabilities, excellent performance, and smooth compatibility with other popular technologies. Such factors make Angular application development a popular choice for building solutions of different size and complexity.

Moreover, to make the developers’ job easier, provide new features, and optimize the existing functionality, Angular releases major updates twice a year. If you want to keep up with these updates, unlock Angular’s new capabilities, and ensure your app’s relevance, opt for the latest version of Angular. 

Today, we will discuss the advantages and best practices for upgrading from an older version of Angular to a new one.

Angular is an open-source front-end software development framework powered by Google. It is primarily used in web development to build dynamic, scalable, and efficient applications with a strong focus on UI/UX design. 

Released in 2016, Angular is the reimagined version of AngularJS, Google’s popular front-end development framework. Angular follows a component-based architecture and uses TypeScript for enhanced maintainability and performance. 

The framework’s latest stable release, Angular 19.2, introduces improvements in performance, developer experience, and advanced features for UI/UX customization. Some of the major updates in Angular 19.1 include:

• Support for TypeScript 5.8 (the latest version of the programming language)
• Enhanced functionality for removing unused standalone components, which optimizes resource consumption and app efficiency
• New templates, devtools, and directives for simplified and effective app development
• Experimental httpResource feature that ensures fast and automated data updates, enhancing app performance
• New components and libraries for UI/UX design implementation.

Overall, the image below illustrates some important features and properties specific to the latest versions of Angular.

Each new Angular release introduces several improvements that can bring tangible benefits to your business. Let’s explore the main benefits of upgrading your Angular app to the latest versions of Angular from a business perspective. 

According to a 2024 report by Deloitte, Chief Information Officers of different businesses spend from 10% to 20% of their budgets to address issues stemming from outdated systems. 

Such expenses are often associated with maintaining, scaling, and expanding the functionality of legacy solutions, and Angular apps are no exception. In addition, outdated user interfaces may frustrate customers and cause issues with an app’s usability. 

As this article focuses on businesses that use Angular for software development, these are the key reasons for modernizing Angular applications. 

Legacy software leads to a poor user experience and makes your software feel outdated. For example, an application built with AngularJS requires extensive boilerplate code and lacks a declarative, component-based architecture. These issues result in significantly lower performance and flexibility compared to modern industry standards.

Unlike legacy versions, modern Angular receives regular security patches and performance enhancements. This ensures compliance with the latest web development standards and simplifies further software improvements. 

Various web apps, including AngularJs and Angular applications, often become a target for several types of attack, namely:

• Cross-site scripting (XXS) attacks, where malicious code is inserted into web pages.
• Cross-site request forgery (CSRF) attacks that may trigger the browser to perform actions without the user’s consent.
• Insecure communication (HTTP) that might expose sensitive information like authentication tokens or personal data.

While Angular provides a rich set of robust security measures, cyber threats evolve rapidly, constantly finding new ways to compromise software safeguards. That’s why it is important to opt for the latest Angular versions, as they provide advanced updates and patches that address up-to-date security threats. For example, Angular 19.2 enhances built-in features like automatic output encoding and strict contextual escaping. Such functionality helps developers mitigate the risk of XSS by ensuring that data is safely inserted into the DOM.

Angular 19.2 introduces several crucial app performance enhancements. The latest version of the framework improves incremental hydration for faster load times and a route-level render mode for better control over SSR (server-side rendering) and CSR (client-side rendering). 

Angular 19.1 also provides Hot Module Replacement (HMR) for templates enabled by default. This feature ensures more convenient app updates in real time. Finally, the latest version of Angular provides faster builds and improved tree-shaking (removal of the dead code). By enhancing resource consumption and boosting the speed of build processes, such updates ensure better software performance. 

Each new Angular update introduces features allowing developers to ensure rapid app development and build complex app front-ends with less effort. 

For example, the latest versions of Angular enhance server-side rendering. This feature gains route-level rendering control, which allows developers to fine-tune how individual routes are rendered and enhance app performance. As a result, Angular developers gain better control over the project and can build stable and high-performing app front ends with less effort.

In addition, Angular constantly expands and adds new libraries with UI/UX components. Its latest version provides developers with access to the most up-to-date selection of such components, ensuring more advanced and convenient app customizability.

Since Google ended support for AngularJS in December 2021, applications built with this framework no longer receive official updates or support. To ensure maintainability and longevity, these solutions should be modernized to newer versions of Angular. Without official patches and updates, an AngularJS-based app can quickly become obsolete, difficult to manage, and prone to performance issues. 

To get regular updates automatically and receive support with new security patches and critical framework fixes, you need the latest versions of Angular. Each major version of the framework typically gets active support for 18 months.  

The terms “Angular update” and “Angular migration” are often used interchangeably. However, in many cases, they describe different scenarios that developers encounter while upgrading an Angular app to the latest version. 

Angular update refers to upgrading from one version of Angular (2+) to a newer version of the framework. This process is generally streamlined using Angular CLI (Command Line Interface) commands, automated tools, the ng update (next-generation update) library, and built-in guides.

Meanwhile, the AngularJS to Angular migration is a much more complex process. It requires a complete architectural shift. AngularJS follows the Model-View-Controller (MVC) paradigm, whereas modern Angular versions use a more efficient, component-based structure enhanced with TypeScript. During such a migration, the developers, typically, rewrite significant parts of the code, using libraries like ngUpgrade (next-generation Upgrade) for hybrid approaches. 

In this article, we will maintain the distinction between an Angular update and an Angular migration to describe different scenarios. 

Updating Angular from a version newer than Angular 2 to the most recent version is much easier than running a full-scale migration from a legacy version of the framework. It typically involves the following steps:

1. Reviewing the existing version and its architecture. During this stage, Angular specialists create a roadmap for the Angular update. They review the critical dependencies, outline core features that should be preserved, and come up with an update plan.

2. Creating a backup. It is important to use the corresponding CLI command to create an app’s backup. It is essential for preventing data loss if the update goes wrong.

3. Updating dependencies. At this stage, software engineers update core dependencies manually or using automation tools. Typically, they begin with core dependencies and then move on to other dependencies, such as updates for related Angular libraries and packages like RxJS.

4. Addressing breaking changes. That’s when software engineers review the changelog for major version updates, fix deprecated APIs, update syntax, and change configurations as needed. 

5. Testing and app deployment. Once all the core update stages are completed, the Angular team applies different quality assurance practices (unit tests, end-to-end tests, etc.) to ensure that the app is running properly. If the testing is successful, it’s time to rebuild and deploy the updated application. 

Below are some tips and best practices for an efficient Angular update.

The official Angular Update Guide provides step-by-step instructions for updating projects. It offers guidelines on breaking changes, best practices, and necessary modifications. The guide covers both manual and automated workflows. 

The Angular Update Guide is a great starting point, but it is unlikely to cover the entire process. For example, using the Angular Update Guide doesn’t fit cases that require code cleanup and refactoring and are associated with strict performance and stability requirements. The point is that the guide provides rather general guidelines more relevant for updating small and mid-load apps with standard architecture. 

The ng command is the CLI tool for managing Angular apps. It includes an update function that automatically identifies outdated dependencies and applies the necessary updates, ensuring compatibility across frameworks. This approach is primarily oriented toward updating simple and straightforward apps. 

By using the ng update command, the developers can minimize manual intervention. Such practice may still be rather time-consuming because the team cannot update an app more than one major version at a time.

If the development team is dealing with complex application dependencies that need to be preserved or optimized, manual effort might be required. This approach to updating Angular apps is often considered the most reliable because the developers can address changes with greater precision. 

However, in many cases, manually updating dependencies is time-consuming and requires strong expertise in Angular software development. Angular specialists review release notes, resolve compatibility issues, and make code adjustments manually. Though tedious, the manual approach provides full control over the update process and ensures a stable and error-free migration. A common practice is running the update with an ng update command while upgrading more complex dependencies manually.

Change detection determines how efficiently Angular updates the UI when data changes. This factor should be considered while upgrading an Angular application because change detection patterns impact the speed of the app. In most cases, older Angular applications rely on default change detection, which can cause performance bottlenecks. 

Meanwhile, while updating an Angular application, developers often migrate it to the OnPush change detection mode. Such an approach minimizes unnecessary re-renders, which improves application responsiveness and performance. This practice is especially relevant when it comes to updating large-scale Angular solutions.

Another common practice used during Angular updates is the adoption of standalone components that simplifies the transition by making app components more self-contained and directly usable. This feature enables a more structured and gradual update by providing a greater isolation of the updated components.  

As a result, development teams can refactor features independently without restructuring entire modules. This practice facilitates faster and more efficient Angular updates.

Below are the most common stages of such a process.

1. Analyzing the existing app and preparing the migration. Software engineers need to review the existing application thoroughly to outline critical migration areas, core dependencies, migration goals, and potential risks and challenges. At this stage, the team creates a migration roadmap and determines its complexity.

2. Creating a backup. Just like in the case of the software update, it is important to create a reliable software backup. It is a standard security practice that ensures that no data or app dependencies are lost in case something goes wrong during migration.

3. Choosing the migration strategy. After the initial project assessment, Angular specialists should choose the most fitting migration approach. The three main options are presented in the table below:

4. Migrating core dependencies and third-party libraries. At this stage, the Angular team identifies deprecated or incompatible libraries and dependencies and upgrades them to fit the new version of the framework.

5. Converting main features. It is the most complex part of the migration, where software engineers should update all the app’s features by upgrading architectural patterns behind them. The team’s approach to this stage depends on the migration strategy chosen during one of the previous stages. 

6. Running tests and fixing issues. Angular software migration can be a complex process. Issues are very likely to occur, so different types of testing, including regression testing, are required. The team can run both manual and automated tests to review the migrated app’s performance in different environments and fix any bugs once they crop out.

7. Deploy the migrated app. Once all the issues are resolved, software engineers can deploy the migrated Angular app. It is important to continue testing and monitoring the application after the migration to avoid performance issues in production. 

Here are some tips that will help your team migrate the Angular app more efficiently. 

If you seek the most reliable approach to Angular migration, incremental updates prove to be the most efficient practice. In this case, an application is migrated version by version without major leaps. 

Incremental updates reduce the risk of breaking changes, which makes them especially relevant to complex apps with sophisticated component dependencies. Typically, Angular developers use automated tools like ngUpgrade to enhance this process and preserve essential app features. Incremental updates are also typically used with a hybrid migration approach where the app continues operating when some of its parts are being upgraded. Overall, this strategy is very reliable but is typically time-consuming. 

This process involves both manual and automated refactoring of crucial components, like APIs, lifecycle hooks, template syntax, and module structures, to make them conform to the standards of modern Angular versions. Skilled JavaScript and TypeScript developers are also required to rewrite the codebase, which can be a time- and effort-consuming task despite many similarities between the languages. 

To allow AngularJS and Angular components to coexist during the migration, developers use upgrade modules. This approach allows the software to keep running during the migration as a hybrid app. Each module can be updated one at a time, ensuring a gradual migration of the entire application. With such practices, the codebase of the Angular app becomes more efficient, flexible, and maintainable. 

To streamline migrations, Angular provides migration schematics — automated scripts designed to update a codebase smoothly. By automating code transformation, this Angular migration tool addresses breaking changes, deprecated features, and necessary modifications, ensuring a seamless transition. This practice allows developers to avoid extensive manual refactoring while maintaining a structured migration process. 

To evaluate the outcomes of your migration, it is important to run different types of tests. In particular, running unit and integration tests before and after updates helps detect regressions early, saving time and costs on debugging post-deployment. Angular teams should also record all their steps and testing results in corresponding documentation to make sure that all the critical information is preserved.

It is important to mention that all these practices can be efficiently combined to achieve the most efficient Angular migration results. To ensure seamless migration from  AngularJS to Angular, teams need to:

• Pay attention to all software dependencies
• Update the legacy architecture and code
• Use relevant Angular migration tools
• Run diverse categories of tests
• Prepare relevant, consistent, and well-organized documentation. 

The main outcome of such a migration is a scalable and flexible application capable of showing great performance and being prepared for upcoming updates.  

Angular migration might be a complex process that requires specific expertise as various bugs and version inconsistencies may crop out, affecting the performance and usability of your solution. Outsourcing Angular migration may be an excellent option when: 

• You lack the required Angular development expertise, which should be especially strong when it comes to complex software migration
• You need to upgrade your application fast without spending much time and budget on hiring and training Angular developers in-house
• You are dealing with an extremely complex legacy software architecture with many hidden dependencies and a significant number of critical components to upgrade
• You want to focus on your core business needs while delegating your Angular app update to a dedicated team capable of handling the entire upgrade
• You are uncertain about potential version compatibility issues that may impact your app’s critical functionality
• You want to get a future-ready codebase that ensures simple maintenance and scaling

Experienced outsourcing companies, like Leobit, conduct in-depth code reviews, which is especially valuable when dealing with legacy versions of Angular. They can identify and resolve inefficiencies, security vulnerabilities, or outdated patterns, helping you both preserve the app’s core functionality and improve it by solving inherent inefficiencies. Outsourcing can be an excellent solution, especially if you lack Angular development expertise, don’t have enough time and budget for hiring in-house developers, or want to focus on your core business goals instead while having the technical side covered.

Upgrading to the latest version of Angular is not just about keeping up with trends. It is a strategic move that will help you enhance your app’s security, performance, and development efficiency while ensuring long-term maintainability. A regular Angular update from a more recent version and migration from AngularJS or other legacy versions of a framework significantly differ in terms of their complexity. However, in both cases, software modernization requires a comprehensive approach that is enhanced with the best practices. 

To minimize risks and maximize the benefits, opt for an experienced Angular software development team. Leobit is ready to provide you with expert Angular developers for such a project. With a solid portfolio of successful Angular projects and experience with a range of other technologies, we will migrate your Angular app seamlessly.

Contact us to discuss your needs and get all the advantages of the latest version of Angular.