Note 84: The DBXadapter driver can adapt dbExpress 3 drivers to dbExpress 4, but not dbExpress 2.5 or older drivers. If your application deploys a native dbExpress 3 driver (not updated to dbExpress 4), you'll also need to distribute the dbxadapter.dll library.
This blog post is part of my "113 Delphi 2007 Handbook Notes" blogging project, to promote my new Delphi book.