YugabyteDB has made significant changes to its YSQL API, including the removal of client certs for authentication in TLS enabled clusters. The default configuration now uses password authentication instead. Three main flags related to TLS are `ysql_enable_auth`, `use_client_to_server_encryption`, and `ysql_hba_conf_csv`. These flags can be used to manually configure a custom HBA (Host-Based Access Control) configuration, which can help with security and performance. Additionally, YugabyteDB has made changes to its role inheritance mechanism, which can cause issues when creating new roles. The YSQL API also supports crosstab queries, also known as pivot queries in Excel, using the tablefunc extension. Furthermore, YugabyteDB offers a choice between having multiple databases with one schema each or one database with multiple schemas, each with their strengths and weaknesses. Finally, the documentation for YugabyteDB is continually being updated and improved, including new content added and changes made to existing documentation.