Major version differences
Encryption property changes
In the Microsoft OLE DB Driver 19 for SQL Server, there are a number of changes made to the encrypt property/connection string keyword.
First, the driver property SSPROP_INIT_ENCRYPT has been changed from a VT_BOOL to a VT_BSTR. The valid values of this property are no/yes/true/false/Optional/Mandatory/Strict. The valid values for the provider connection string keyword Encrypt have changed from no/yes to no/yes/true/false/Optional/Mandatory/Strict. Similarly, for the IDataInitialize connection string keyword Use Encryption for Data, the valid values have changed from true/false to no/yes/true/false/Optional/Mandatory/Strict. The Optional value is synonymous with the old no/false values and the Mandatory value is synonymous with the old yes/true values. Strict is a new value added in version 19.0.0 of the OLE DB Driver for SQL Server and encrypts PRELOGIN packets in addition to all other communication with the server. Strict encryption is only supported on SQL Server endpoints that support TDS 8.0, otherwise the driver will fail to connect. The OLE DB Driver 19 for SQL Server continues to support all legacy keyword values for backwards compatibility.
Second, the default value has changed from no/false to Mandatory. This change means that connections are encrypted by default. Previously, the driver would encrypt connections if explicitly set by the user and/or mandated by the SQL Server when the server side property Force Encryption was set to yes. To use old default behavior, include Encrypt=Optional; in the provider connection string, or Use Encryption for Data=Optional; in the IDataInitialize connection string.
Driver name changes
The new Microsoft OLE DB Driver 19 for SQL Server supports side by side installation with the older Microsoft OLE DB Driver for SQL Server. To be able to differentiate the drivers, the name was changed to include the major version number. To use the new driver in an application, the user must specify the new driver name. The new driver name, along with the corresponding CLSID, is specified in the updated msoledbsql.h header that must be included in the project. Connections through the IDBInitialize interface require no further changes since MSOLEDBSQL_CLSID will specify the CLSID of the OLE DB Driver 19 for SQL Server. Connections through the IDataInitialize interface must replace the value of the Provider keyword with MSOLEDBSQL19 to use the Microsoft OLE DB Driver 19 for SQL Server. In graphical user interfaces such as data link properties or linked server setup in SSMS, "Microsoft OLE DB Driver 19 for SQL Server" must be selected from the list of installed providers.
See also
OLE DB Driver for SQL Server
Using Connection String Keywords with OLE DB Driver
Encryption and certificate validation
Universal Data Link (UDL) Configuration
SQL Server Login Dialog Box (OLE DB)
Initialization and authorization properties (OLE DB driver)
Registry settings