The default value for the SslMode connection option now differs based on the protocol used to make the connection. The Preferred mode has been reintroduced in this release (see Options for Both Classic MySQL Protocol and X Protocol). To summarize the default Sslmode values in the Connector/NET 8.0 (and 7.0) release series:

Connector/NET 8.0.13: Preferred mode is the default for classic MySQL protocol connections only. Required mode is the default for X Protocol connections only (Preferred mode is not available for use with X Protocol).

Connector/NET 8.0.8 to 8.0.12: Preferred mode is not supported for any connections. Required mode is the default for both classic MySQL protocol and X Protocol connections.

Connector/NET 7.0.0 to 7.0.7: Preferred mode is the default for both classic MySQL protocol and X Protocol connections. (Bug #28687769)

Document Store: An incremental improvement was made to the performance of session creation with a connection string. (Bug #28343655)

Support for EF Core 2.1 was added to Connector/NET 8.0.13 and support for EF Core 2.0 was discontinued in the same connector version. Other versions of Connector/NET continue to support EF Core 2.0 (see Entity Framework Core Support). (WL #12182)

The ConnectionTimeout connection option and property were reimplemented as the Connect-Timeout option (and the ConnectTimeout property) for X Protocol operations. Some aspects of the timeout behavior were changed (see Options for X Protocol Only).

The new ConnectTimeout property was added to the MySqlX.XDevAPI.MySqlXConnectionStringBuilder class and the existing ConnectionTimeout property was removed.

No modifications were made to the existing implementation of the ConnectionTimeout option (or property) for classic MySQL operations. (WL #12177)

Connector/NET now provides connection pooling for applications using the X Protocol. The implementation includes the new static MySQLX.GetClient method that takes two parameters: connectionData (connection string or URI) and connectionOptions (JSON-formatted string or anonymous object containing the pooling options). Method overloading enables the following type combinations:

MySQLX.GetClient(Object, Object)
MySQLX.GetClient(Object, String)
MySQLX.GetClient(String, Object)
MySQLX.GetClient(String, String)

GetClient returns the new Client object, which retrieves an existing and currently unused network connection from the pool, resets it, and uses it. Closing a session marks the underlying connection as unused and returns it to the pool. Connection options are configured as follows:

// Connection options of type String
Client client = MySQLX.GetClient(ConnectionData, "{ \"pooling\": { \"maxSize\":  5, \"queueTimeout\": 5000 } }");

// Connection options of type Object (anonymous object)
Client client = MySQLX.GetClient(ConnectionData, new { pooling = new { maxSize = 5, queueTimeout = 5000 } });

The new keyword must be used twice when the connection options are configured using an anonymous object. Connection options are: enabled, maxSize, maxIdleTime, and queueTimeout. For more information, see Connection and Session Concepts. (WL #11841)

The CreateCommandBuilder and CreateDataAdapter methods were added to MySqlClientFactory class. Thanks to Cédric Luthi for the patch. (Bug #28560189, Bug #92206)

Document Store: Connector-side validation performed when the Collection.CreateIndex method was called duplicated some of the checks already made by the server. The connector now only validates that the indexDefinition value passed to the method is a valid JSON document with the correct structure. (Bug #28343828)

EF Core: An invalid syntax error was generated when a new property (defined as numeric, has a default value, and is not a primary key) was added to an entity that already contained a primary-key column with the AUTO_INCREMENT attribute. This fix validates that the entity property (column) is a primary key first before adding the attribute. (Bug #28293927)

Connector/NET returned the wrong time zone when the TIMESTAMP column was read from a MySQL table. (Bug #28156187)

Document Store: A mixed alphanumeric value such as "1address" when used with the Set and Unset methods caused the operations to throw an exception. This fix resolves the way mixed values are converted into tokens to generate only one token as an identifier. (Bug #28094094)

EF Core: The implementation of some methods required to scaffold an existing database were incomplete. (Bug #27898343, Bug #90368)

Attempts to create a new foreign key from within an application resulted in an exception when the key was generated by a server in the MySQL 8.0 release series. (Bug #27715069)

A variable of type POINT when used properly within an application targeting MySQL 8.0 generated an SQL syntax error. (Bug #27715007)

The implementation of DbProviderFactory prevented an application from connecting to MySQL in a generic way. Now, invoking the CreateDataAdapter method returns a valid adapter instead of returning the null value. (Bug #27292344, Bug #88660)

The case-sensitive lookup of field ordinals was initialized using case-insensitive comparison logic. This fix removes the original case-sensitive lookup. (Bug #27285641, Bug #88950)

The MySql.Data.Types.MySqlGeometry constructor called with an array of bytes representing an empty geometry collection generated an ArgumentOutOfRangeException exception, rather than creating the type as expected. Thanks to Peet Whittaker for the patch. (Bug #26421346, Bug #86974)

Slow connections made to MySQL were improved by reducing the frequency and scope of operating system details required by the server to establish and maintain a connection. (Bug #22580399, Bug #80030)