WinZip 18.0 was released near the end of October 2013. The original release and standard installation files will not work with Windows XP or Windows Server 2003. To install WinZip 18.0 on Windows XP or Server 2003, you will need to download the specific WinZip 18 for XP installation file.
As explained in the Windows lifecycle fact sheet, extended support for Windows XP will end on April 8, 2014. WinZip also discontinues supporting Windows versions as their life cycle ends. It is expected that this WinZip 18.0 version will be the last WinZip version that will install on or work on Windows XP and/or Windows Server 2003.
WinZip 18.0 for XP includes an upgraded WinZip 18 zip engine. This will provide the ability to unzip any Zipx files you receive, including ones in which the XZ compression method was used. However, it will not create Zipx files using the XZ compression method. You should keep in mind that some of the other new features in WinZip 18, like the Cloud Services, are not supported due to the lack of a ribbon interface in Windows XP.
If you have any questions about this information please email Technical Support.