GitHub Enterprise 2.21 introduces several new features and enhancements aimed at improving pull requests, issues, notifications, and overall platform performance. Notably, users can now convert existing pull requests into drafts and make multi-line suggestions during code reviews, which streamlines the development process. The update also allows for easier linking of issues to pull requests, enhancing visibility within project board views. A revamped notifications system increases the likelihood of timely responses by allowing users to customize filters and workflows. Performance improvements include faster backup and restore processes and the introduction of new repository permission roles, triage and maintain, for finer access control. Additionally, several API updates have been implemented, such as enabling deployment deletions and supporting scaling in Teams and Reactions APIs, while phasing out some legacy webhook events. These changes aim to foster innovation and efficiency on the platform while maintaining security and reliability.