All versions can be installed on a system at the same time.
All versions expose the same properties, methods and events.
The ActiveX controls are easily interchangeable in your application without code changes. Beginning with V3.0, the Webster Pro Control is available in three functionally identical versions. If you are not sure of which version to use then the S-Type is probably your best choice to start with. You can always switch to a D-Type later if you decide to distribute the support DLLs with your application. This is the same as previous 32-bit versions of the control and requires no change to existing installation procedures.