The short answer is Yes, the current version of WinZip is compatible with older WinZip versions and other Zip file utilitites. However, you must consider what options you are using and other factors when creating your Zip files (.zip or .zipx) to insure compatibility. If you are sharing your Zip files with others, it is recommended that you find out what Zip file utility they have installed. Legacy compression is the safest to use when you are not sure.
WinZip 12.1 and later provides several methods for compressing the files that you add to a Zip file. In making a choice of compression method, there are several things to consider, including the type of data you are compressing, your plans for later unzipping the data, and the amount of time you are willing to wait while your data is being compressed.
In most cases, WinZip provides three basic choices for compression method:
- .Zip: Legacy compression: This method, referred to as Maximum Deflate in earlier versions of WinZip, provides good, fast compression that is compatible with virtually all Zip file utilities. You may want to choose this option if speed of compression is a primary concern or if you are sending the Zip file to others who may not have a Zip file utility that can extract files compressed with newer methods.
- .ZipX: Best method: This choice allows WinZip to choose the best compression method for each file, based on the file type. You may want to choose this option if compressed file size is a primary concern. Choosing best method will result in a Zipx file, so if you are planning to share these Zip files with others, you should be sure that they are using WinZip 12.1 or later. The Jpeg compression and WavPack compression methods are only available when using Best method.
- Let me choose: If you choose this option you can select a specific compression method from a list that includes None, SuperFast, Enhanced Deflate, bzip2, LZMA, and PPMd. Choosing bzip2, LZMA or PPMd will result in the creation of a Zipx file.
When considering compatibility of the Zip files you create with WinZip, you should also be aware of two additional extensions to the Zip file format. Although WinZip has published the specifications for these format extensions and many Zip file utilities can extract from Zip files using them, not all Zip file utilities will be able to do so.
- 128- and 256-bit key AES encryption: AES encryption provides much greater cryptographic security than the traditional Zip 2.0 encryption method used in earlier versions of WinZip. WinZip's AES encryption (FIPS-197 certified) uses the Rijndael cryptographic algorithm which, in 2001, was specified by the National Institute of Standards and Technology (NIST) in Federal Information Processing Standards (FIPS) Publication 197 as the Advanced Encryption Standard (AES).
- 64-bit extensions: The Zip 2.0 format imposed restrictions on how large a Zip file could be, and the number of files it could contain. For all practical purposes, the 64-bit extended format eliminates all these restrictions. Using the extended format, the member file size, Zip file size, and number of member files you can add to a Zip file are limited only by your system's resources. WinZip uses the 64-bit extended format; however, only when the limits of the original format are exceeded. (The original Zip file format limited the number of member files in a Zip file to 65,535, and the maximum size of both the Zip file itself and any member file to 4 gigabytes.)
Please e-mail Technical Support if you have additional questions.
