caching_sha2_passwordauthentication mechanism is now supported due to the MySQL client library update to 5.7.23.
The Unicode version now uses the UTF8MB4 character set as a transport character set between the MySQL server and the ODBC driver. Because text conversions requested by the ODBC user with the CHARSET connection option are done inside the ODBC Driver after the data is received from the server, it now converts text data as UTF8MB4 to USER_CHARSET instead of UTF8 to USER_CHARSET. (Bug #28204756)
Connections to MySQL Server 8.0 could yield "Source character set not supported by client" errors during sorting and case-sensitive operations. Now known UTF8MB4 collations are used for these operations, such as utf8mb4_general_ci (known to libmysqlclient 5.7) instead of utf8mb4_tolower_ci. (Bug #28116892, Bug #90984)
MySQL Server 8.0 connections could fail with unsupported character sets and collations as utf8mb4_xxxxxx collations reported by MySQL Server 8.0 with numbers greater than 250 were unknown to libmysqlclient 5.7. Because collations affect sorting but not the data conversion, they can be substituted with known collations such as utf8mb4_general_ci (45). (Bug #28116892, Bug #90984)
Connector/ODBC is now built with MySQL client library 5.7.23, and commercial builds also use an updated OpenSSL version (v1.0.2o). Issues fixed in the new OpenSSL version are described at http://www.openssl.org/news/vulnerabilities.html. (Bug #27829777)
Reported errors that occurred while executing multiple statements with a single query were generic and without context. For example, SQLMoreResults might return "unhandled error from mysql_next_result()" instead of the error reported by MySQL Server. (Bug #11757423, Bug #49466)