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Field TZipHeader.RequiredVersion

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Version needed to extract (2 bytes)







Code (Delphi)

RequiredVersion: UInt16;



The minimum supported ZIP specification version needed to extract the file. This value is based on the specific format features a ZIP program must support to be able to extract the file. If multiple features are applied to a file, the minimum version should be set to the feature having the highest value. New features or feature changes affecting the published format specification will be implemented using higher version numbers than the last published value to avoid conflict.Current minimum feature versions are as defined below:

1.0 - Default value
1.1 - File is a volume label
2.0 - File is a folder (directory)
2.0 - File is compressed using Deflate compression
2.0 - File is encrypted using traditional PKWARE encryption
2.1 - File is compressed using Deflate64(tm)
2.5 - File is compressed using PKWARE DCL Implode
2.7 - File is a patch data set
4.5 - File uses ZIP64 format extensions
4.6 - File is compressed using BZIP2 compression (1)
5.0 - File is encrypted using DES
5.0 - File is encrypted using 3DES
5.0 - File is encrypted using original RC2 encryption
5.0 - File is encrypted using RC4 encryption
5.1 - File is encrypted using AES encryption
5.1 - File is encrypted using corrected RC2 encryption (2)
5.2 - File is encrypted using corrected RC2-64 encryption (2)
6.1 - File is encrypted using non-OAEP key wrapping (3)
6.2 - Central directory encryption
6.3 - File is compressed using LZMA
6.3 - File is compressed using PPMd (4)
6.3 - File is encrypted using Blowfish
6.3 - File is encrypted using Twofish



(1) Early 7.x (pre-7.2) versions of PKZIP incorrectly set the version needed to extract for BZIP2 compression to be 50 when it should have been 46.



(2) Refer to the section on Strong Encryption Specification for additional information regarding RC2 corrections.



(3) Certificate encryption using non-OAEP key wrapping is the intended mode of operation for all versions beginning with 6.1. Support for OAEP key wrapping should only be used for backward compatibility when sending ZIP files to be opened by versions of PKZIP older than 6.1 (5.0 or 6.0).



(4) Files compressed using PPMd should set the version needed to extract field to 6.3, however, not all ZIP programs enforce this and may be unable to decompress data files compressed using PPMd if this value is set. When using ZIP64 extensions, the corresponding value in the zip64 end of central directory record should also be set. This field should be set appropriately to indicate whether Version 1 or Version 2 format is in use.



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See also

Send feedback... Build date: 2018-11-26
Last edited: 2018-11-26
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