Greenfield projects allow developers to design APIs without legacy constraints, but as they progress, the decision on how to manage API updates becomes crucial. The article explores the debate between explicit versioning and evolving APIs while maintaining backward compatibility, focusing on GraphQL and RESTful APIs. Roy Fielding's REST architecture doesn't explicitly discuss versioning, highlighting the importance of stateless interactions and media types, which can support either approach. GraphQL, however, favors evolution by enabling older clients to ignore new features without breaking, through its flexible query language. Versioning, often necessary when changes could break client functionality, uses schemes like Semantic Versioning and can be implemented through URLs or request headers, each with pros and cons. The discussion emphasizes the need for consistent strategies and clear communication with users, whether opting for versioning or evolution.