Deprecation of features is a common practice in software development, allowing developers to focus on new and improved functionalities while maintaining transparency with users. The Deprecation Policy of Cube.js aims to provide clear guidelines for the removal of outdated or less-used features, ensuring a smoother transition for users. By marking deprecated features in documentation and release notes, providing migration instructions, and setting specific dates for removal, developers can plan accordingly and avoid potential disruptions. As part of this effort, notable features such as contextToDataSourceId configuration option replacement, CUBEJS_ENABLE_TLS configuration option removal, support for Node.js 8 end-of-life, and embedding Cube.js within Express removal are planned to be deprecated in future releases.