Throughout the evolution of Xceed Zip Compression Library, up until version 4.0, all 16- and 32-bit components shared the same programmatic interface. That means that as new components and features were added and Xceed Zip evolved from versions 1.0 to 3.5, all the controls offered by the library were programmed using the same properties, methods and events. When a new feature was added, and even when 32-bit support was introduced, Xceed Zip users required no modifications to their code.

Starting with Xceed Zip v4.0, which is an entirely new product based on a different programming paradigm and compression engine, an entirely new programming interface was designed and implemented. Xceed Zip versions 4.0 and up have some fundamental differences with Xceed Zip v3.5 in the way that they processes files, scan drives, fire events and handle the compressed data. Changing the programming interface has brought some definite advantages to the library. Xceed Zip v4.x's and v6.x's new interface offers developers a lot more flexibility and control, yet is more easier to use than ever. New users will get started faster, and veterans will enjoy the new flexibility offered by the library.

New Xceed Zip v4.x ActiveX control follows the COM standard and all new versions and releases will remain compatible with the existing published interfaces. In no event shall the updating of the XCEEDZIP.DLL file affect existing applications.

The properties, methods and events used for Xceed Zip versions 1.0 to 3.5 have changed for Xceed Zip 4.x, 5.x,   and 6.x. Some have simply been renamed. Others no longer exist, and many work differently. If your existing applications that use Xceed Zip 1.0 to 3.5 wish to use the new features of Xceed Zip 6.x, some of your code must be modified. The "Migration" section of the Xceed Zip  manual will guide you through the changes you must make in order to get your code ready for using the new Xceed Zip ActiveX control.

The code changes are outlined by the following topics: