Assuming you want to know how to keep the build environment constant throughout the product's life:
The best way to preserve the build environment is by using containers. Containers allow you to package up an application with all of the parts it needs, such as libraries and other dependencies, and ship it all out as one package. This means that your application will always have the same dependencies no matter where you deploy it.
There are a few different container technologies out there, but Docker is the most popular. If you're using Docker, you can specify exactly which version of each dependency your application needs in a Dockerfile. Then, when you build your Docker image, it will pull in those specific versions and package them up along with your application code.
Alternatively, you could use a tool like Vagrant to create and manage a virtual machine that mimics your production environment. This can be helpful if you need to test how your application will behave in a production-like environment.