Ruby 3.3 has been released, featuring a new parser called Prism, a pure-Ruby JIT compiler named RJIT, and significant performance improvements, especially with YJIT. The release also includes a new M:N thread scheduler, improved garbage collection, and various updates to the standard library. Ruby 3.3 is considered a major release with many new features and improvements. The release is available for download with various checksums provided for verification.