With the introduction of BDS 2006, there is a new dbExpress protocol, which is version 3.0. Older protocols are considered to be version 2.5. Protocol 3.0 mainly adds WideString (UNICODE) support, native int8 support and a few new interfaces. Please check Section 1, “Multibyte, UNICODE and Locales” for details.

The pgExpress Driver supports both protocols, in addition to Kylix support, all in one package. Protocol 3.0 drivers, however, will work only with BDS 2006 or later applications; protocol 2.5 drivers should work with any application designed for dbExpress.

The protocol 3.0 drivers have a '30' suffix labeled in their names, such as:

dbexppge30.dll
dbexppge30-ml.dll

You can either rename the "30" files to the traditional "dbexppge.dll file name, or change the dbxconnections(.ini)/TSQLConnection entry to point to the new file name.

The pgExpress Driver is the first third-part dbExpress driver to implement the protocol 3.0 interfaces.