Since a new version is coming out every year, Oracle’s release roadmap introduced two types of annual releases. Interim releases (20c, 21c) are supported for 2 (or 3) years - only premium support, no extended support. Long-term releases (19c, 22c) have 4 years of premium support and and 2+ years extended support.
Thanks to the Oracle Cloud team to provide a good environment where DBA's can create and use latest version of Oracle 21c with a few clicks in OCI you can create a DB system with Oracle 21c. Then nothing else standing in the way to test new features.
You can refer the below link to watch Demo.