Two years ago, Bit introduced major updates to its component development environments (envs), offering enhanced control, flexibility, and improved developer experience through a decoupled structure allowing independent versioning, customizable configuration files, and seamless ESM support. The upgrades facilitate easier modifications, increased visibility, and stability, with two main migration paths: creating a new Bit env with desired configurations or completely refactoring the existing implementation. This blog post outlines the process for creating a new Bit env using React as a base, detailing steps for generating, replacing, and updating env configurations, while noting key changes in base configurations such as the shift from CJS to ESM and Jest updates across various frameworks. Users now have direct access to tooling configurations, can apply themes to compositions, and manage dependency definitions through a straightforward env.jsonc configuration file.