What is Zipx?
WinZip® 12.1 introduced the new .zipx file extension, the next step in the evolution of the Zip file format. By using the most recent compression methods to create Zipx files, WinZip 12.1 or later creates WinZip's smallest Zip files to date. The new .zipx file extension also makes it easier to share highly compressed files with others by making it clear that the file was created using advanced methods and that WinZip 12.1 (or later) or another compatible compression utility is required to open the file.
All details associated with creating and reading Zipx files are documented for use by software developers of compression software, anti-virus software, search engines, and other software applications. Please see the WinZip website for the latest details.