One of the best parts about removing libraries, such as animations, from Angular 4's core dependencies is that we can now decide whether we want to or not. If our application doesn't need any animation capability, it is completely safe for us to not include it as a dependency in our package.json or as a part of our NPM install upgrade command. If we change our mind later, we can always install the animation library when the need arises. Depending on the functionality of your web application, you may also be able to do without the router, forms, or HTTP libraries.

Once your upgraded Angular 4 application successfully compiles, ensure that you take time to check that all your existing automated tests and the application functionality itself continue to function as expected. Assuming that your application is functioning properly, you will be enjoying an approximately 25% smaller generated file size as well as access to the new APIs and features.