SAA-C02 and SAA-C03 refer to different versions of the AWS Certified Solutions Architect - Associate exam. The main difference lies in the content and focus of each version. SAA-C02, released in 2020, covers AWS services and architectural best practices up until that point. On the other hand, SAA-C03, the updated version released in 2022, reflects the latest changes and additions to the AWS platform. It incorporates newer services, architectural patterns, and industry trends, ensuring certified professionals have the most up-to-date knowledge and skills. Aspiring candidates must prepare for the specific version they are targeting, as the exam content and objectives may vary between SAA-C02 and SAA-C03.