This is the Github Page of 7-Zip ZS with support of additional Codecs. The library used therefore is located here: Multithreading Library

You can install it in two ways:

1. complete setup with additions within the GUI and a modified Explorer context menu
2. only the codec plugin that goes to your existing 7-Zip installation (no GUI changes and no additional Hashers)

1. Zstandard v1.5.7 is a real-time compression algorithm, providing high compression ratios. It offers a very wide range of compression / speed trade-off, while being backed by a very fast decoder.

   • Levels: 1..22

2. Brotli v.1.2.0 is a generic-purpose lossless compression algorithm that compresses data using a combination of a modern variant of the LZ77 algorithm, Huffman coding and 2nd order context modeling, with a compression ratio comparable to the best currently available general-purpose compression methods. It is similar in speed with deflate but offers more dense compression.

   • Levels: 0..11

3. LZ4 v1.10.0 is lossless compression algorithm, providing compression speed at 400 MB/s per core (0.16 Bytes/cycle). It features an extremely fast decoder, with speed in multiple GB/s per core (0.71 Bytes/cycle). A high compression derivative, called LZ4_HC, is available, trading customizable CPU time for compression ratio.

   • Levels: 1..12

4. LZ5 v1.5 is a modification of LZ4 which was meant for a better ratio at cost of slower compression and decompression. It's superseded by Lizard now.

   • Levels: 1..15

5. Lizard v2.1 is an efficient compressor with fast decompression. It achieves compression ratio that is comparable to zip/zlib and zstd/brotli (at low and medium compression levels) at decompression speed of 1000 MB/s and faster.

   • Levels 10..19 (fastLZ4) are designed to give about 10% better decompression speed than LZ4
   • Levels 20..29 (LIZv1) are designed to give better ratio than LZ4 keeping 75% decompression speed
   • Levels 30..39 (fastLZ4 + Huffman) adds Huffman coding to fastLZ4
   • Levels 40..49 (LIZv1 + Huffman) give the best ratio, comparable to zlib and low levels of zstd/brotli, but with a faster decompression speed

6. Fast LZMA2 v1.0.1 is a LZMA2 compression algorithm, 20% to 100% faster than normal LZMA2 at levels 5 and above, but with a slightly lower compression ratio. It uses a parallel buffered radix matchfinder and some optimizations from Zstandard. The codec uses much less additional memory per thread than standard LZMA2.

   • Levels: 1..9

7z and 7zz provide largely the same core 7‑Zip functionality, but they are built/distributed differently (plugin-capable vs. standalone), which can affect available formats/codecs.

1. download the setup from here 7-Zip ZS Releases
2. install it, like the default 7-Zip one
3. you may check, if the 7-Zip can deal with Zstandard or other codecs via this command: 7z.exe i

The output should look like this:

7-Zip 25.01 ZS v1.5.7 (x64) : Copyright (c) 1999- Igor Pavlov, 2016- Tino Reichardt, 2022- Sergey G. Brester : 2025-08-06

Libs:
 0  c:\Program Files\7-Zip-Zstandard\7z.dll
 1  C:\Program Files\7-Zip-Zstandard\Codecs\Iso7z.64.dll
 
Formats:
...
 0 CK            xz       xz txz (.tar) FD 7 z X Z 00
 0               Z        z taz (.tar)  1F 9D
 0 CK            zstd     zst zstd tzst (.tar) tzstd (.tar) 0 x F D 2 F B 5 2 5 . . 0 x F D 2 F B 5 2 8 00
 0 C   F         7z       7z            7 z BC AF ' 1C
 0     F         Cab      cab           M S C F 00 00 00 00
...

Codecs:
 0 4ED   303011B BCJ2
 0  EDF  3030103 BCJ
 0  EDF  3030205 PPC
 0  EDF  3030401 IA64
 0  EDF  3030501 ARM
 0  EDF  3030701 ARMT
 0  EDF  3030805 SPARC
 0  EDF    20302 Swap2
 0  EDF    20304 Swap4
 0  ED     40202 BZip2
 0  ED         0 Copy
 0  ED     40109 Deflate64
 0  ED     40108 Deflate
 0  EDF        3 Delta
 0  ED        21 LZMA2
 0  ED     30101 LZMA
 0  ED     30401 PPMD
 0   D     40301 Rar1
 0   D     40302 Rar2
 0   D     40303 Rar3
 0   D     40305 Rar5
 0  ED   4F71102 BROTLI
 0  ED   4F71104 LZ4
 0  ED   4F71106 LIZARD
 0  ED   4F71105 LZ5
 0  ED   4F71101 ZSTD
 0  ED        21 FLZMA2
 0  EDF  6F10701 7zAES
 0  EDF  6F00181 AES256CBC

Hashers:
 0   32      202 BLAKE2sp
 0   32      204 BLAKE3
 0    4        1 CRC32
 0    8        4 CRC64
 0   16      205 MD2
 0   16      206 MD4
 0   16      207 MD5
 0   20      201 SHA1
 0   32        A SHA256
 0   48      208 SHA384
 0   64      209 SHA512
 0   32      20A SHA3-256
 0   48      20B SHA3-384
 0   64      20C SHA3-512
 0    4      20D XXH32
 0    8      20E XXH64

In summaray: It's not maleware - but it's not my job to chase after these (snake oil manufacturers)[https://en.wikipedia.org/wiki/Snake_oil].

In detail: you can verify for yourself that the release downloads are generated on the fly by GitHub Actions on this Microsoft-owned platform. If there really were any viruses, they would be generated by machines running in Microsoft data centers 😉

For example, for the released version v25.01-v1.5.7-R4:

• it's the one with tag v25.01-v1.5.7-R4
• click on Adjust Blake3 MAX_SIMD_DEGREE
• scroll down to the Artifacts section
• all the windows binaries are within this ZIP file: 7-Zip ZS Release binaries.zip
• check if the SHA256 hashsums are the same as the files of the release

I started a list of false positive issues with issue #451. Please don’t open a new issue. Instead, contact the antivirus vendor and ask them to remove this false positive.

• compression and decompression for Brotli, Lizard, LZ4, LZ5 and Zstandard within the 7-Zip container format
• compression and decompression of Brotli (.br), Lizard (.liz), LZ4 (.lz4), LZ5 (.lz5) and Zstandard (.zst) files
• handling of ZIP files with Zstandard compression
• included lzip decompression support, patch from: https://download.savannah.gnu.org/releases/lzip/7zip/
• explorer context menu: "Add to xy.7z" will use all parameters of the last "Add to Archive" compression dialog (this includes: method, level, dictionary, blocksize, threads and paramters input box)
• squashfs files with LZ4 or Zstandard compression can be handled
• several history settings aren't stored by default, look here for some info about that, you can restore original 7-Zip behavior via tools->options->settings
• these hashes can be calculated: CRC32, CRC64, MD2, MD4, MD5, SHA1, SHA256, SHA384, SHA512, SHA3-256, SHA3-384, SHA3-512, XXH32, XXH64, BLAKE2sp, BLAKE3 (lowercase or uppercase)

7z a archiv.7z -m0=zstd -mx0   Zstandard Fastest Mode, without BCJ preprocessor
7z a archiv.7z -m0=zstd -mx1   Zstandard Fast mode, with BCJ preprocessor on executables
7z a archiv.7z -m0=zstd -mx..  ...
7z a archiv.7z -m0=zstd -mx21  Zstandard 2nd Slowest Mode, with BCJ preprocessor on executables
7z a archiv.7z -m0=zstd -mx22  Zstandard Ultra Mode, with BCJ preprocessor on executables

7z a archiv.7z -m0=lz4 -mx0   LZ4 Fastest Mode, without BCJ preprocessor
7z a archiv.7z -m0=lz4 -mx1   LZ4 Fast mode, with BCJ preprocessor on executables
7z a archiv.7z -m0=lz4 -mx..  ...
7z a archiv.7z -m0=lz4 -mx12  LZ4 Ultra Mode, with BCJ preprocessor on executables

7z a archiv.7z -m0=lz5 -mx0   LZ5 Version 1.5 Fastest Mode, without BCJ preprocessor
7z a archiv.7z -m0=lz5 -mx1   LZ5 Version 1.5 Fast mode, with BCJ preprocessor on executables
7z a archiv.7z -m0=lz5 -mx..  ...
7z a archiv.7z -m0=lz5 -mx16  LZ5 Version 1.5 Ultra Mode, with BCJ preprocessor on executables

7z a archiv.7z -m0=flzma2 -mx1   Fast LZMA2 Fastest mode, with BCJ preprocessor on executables
7z a archiv.7z -m0=flzma2 -mx..  ...
7z a archiv.7z -m0=flzma2 -mx9   Fast LZMA2 Ultra Mode, with BCJ preprocessor on executables

7z x -so test.tar.zst | 7z l -si -ttar
-> show contents of zstd compressed tar archive test.tar.zst

7z x -so test.tar.lz | 7z l -si -ttar
-> show contents of lzip compressed tar archive test.tar.lz

1. download the Codecs.7z archive from here 7-Zip ZS Releases, this archive holds binaries, which are compatible with the Mainline version of 7-Zip
2. create a new directory named Codecs and put in there the zstd-x32.dll or the zstd-x64.dll, depending on your 7-Zip installation
   • normally, the x32 should go to: "C:\Program Files (x86)\7-Zip\Codecs"
   • the x64 version should go in here: "C:\Program Files\7-Zip\Codecs"
3. you could also replace the 7z.dll directly within C:\Program Files (x86)\7-Zip
4. then you may check if the dll is correctly installed via this command: 7z.exe i

The output should look like this:

7-Zip 21.03 (x64) : Copyright (c) 1999-2021 Igor Pavlov : 2021-05-06

Libs:
 0  C:\Program Files\7-Zip\7z.dll

Libs:
 0  c:\Program Files\7-Zip\7z.dll
 1  c:\Program Files\7-Zip\Codecs\brotli-x64.dll
 2  c:\Program Files\7-Zip\Codecs\flzma2-x64.dll
 3  c:\Program Files\7-Zip\Codecs\lizard-x64.dll
 4  c:\Program Files\7-Zip\Codecs\lz4-x64.dll
 5  c:\Program Files\7-Zip\Codecs\lz5-x64.dll
 6  c:\Program Files\7-Zip\Codecs\zstd-x64.dll

...

Codecs:
 0 4ED  303011B BCJ2
 0  ED  3030103 BCJ
 0  ED  3030205 PPC
 0  ED  3030401 IA64
 0  ED  3030501 ARM
 0  ED  3030701 ARMT
 0  ED  3030805 SPARC
 0  ED    20302 Swap2
 0  ED    20304 Swap4
 0  ED    40202 BZip2
 0  ED        0 Copy
 0  ED    40109 Deflate64
 0  ED    40108 Deflate
 0  ED        3 Delta
 0  ED       21 LZMA2
 0  ED    30101 LZMA
 0  ED    30401 PPMD
 0   D    40301 Rar1
 0   D    40302 Rar2
 0   D    40303 Rar3
 0   D    40305 Rar5
 0  ED  6F10701 7zAES
 0  ED  6F00181 AES256CBC
 1  ED  4F71102 BROTLI
 2  ED       21 FLZMA2
 3  ED  4F71106 LIZARD
 4  ED  4F71104 LZ4
 5  ED  4F71105 LZ5
 6  ED  4F71101 ZSTD

• compression and decompression for Brotli, Fast LZMA2, Lizard, LZ4, LZ5 and Zstandard within the 7-Zip container format
• you can only create .7z files, the files like .lz4, .lz5 and .zst are not covered by the plugins
• when compressing binaries (*.exe, *.dll), you have to explicitly disable the bcj2 filter via -m0=bcj, when using only the plugin dll's
• so the usage should look like this:

7z a archiv.7z -m0=bcj -m1=zstd -mx1   Fast mode, with BCJ preprocessor on executables
7z a archiv.7z -m0=bcj -m1=zstd -mx..  ...
7z a archiv.7z -m0=bcj -m1=zstd -mx21  2nd Slowest Mode, with BCJ preprocessor on executables
7z a archiv.7z -m0=bcj -m1=zstd -mx22  Ultra Mode, with BCJ preprocessor on executables
7z a archiv.7z -m0=bcj -m1=brotli -mxN  ...
7z a archiv.7z -m0=bcj -m1=lizard -mxN  ...
7z a archiv.7z -m0=bcj -m1=lz4 -mxN  ...
7z a archiv.7z -m0=bcj -m1=lz5 -mxN  ...
7z a archiv.7z -m0=bcj -m1=flzma2 -mxN  ...

There is no dedicated plugin for Total Commander anymore, and it seems that the files tc7z.dll and tc7z64.dll cannot simply be replaced at the moment.

• copy the 7z.dll file from C:\Program Files\7-Zip-Zstandard\7z.dll to C:\Program Files\Far Manager\Plugins\ArcLite\7z.dll
• then restart the Far manager - and on next start, you will have support for 7-Zip Zstandard archives ;-)

For benchmarking, I started using the Linux binary 7zz in 2026.

The test system is an idle Dell PowerEdge R6615 with the following hardware:

• CPU: AMD EPYC 9354P (32 cores)
• Memory: 128 GB DDR5 (8x 16GB)
• OS: AlmaLinux 9 (x86_64)

For the tests, the Silesia compression corpus is used.

Compression tests are performed by running a single-threaded compression for each method: 7z a test.7z -mmt=1 -m0=MethodX.

Decompression is tested on the freshly created archive using: 7z t test.7z. Memory usage and execution times are measured using a modified GNU time. The benchmarks themselves are executed via a shell script.

Results:

• FileManager Toolbar Icon Theme: Glyfz 2016 by AlexGal homepage
• File Types Icon Theme: Windows 10 by masamunecyrus homepage
• Additional icons file types created by Mr4Mike4 homepage
• Dark mode support via darkmodelib (v0.47.0) by ozone10 homepage

• The same as the Mainline 7-Zip, which means most of the code is GNU LGPL v2.1-or-later
• Read COPYING for more details

• 7-Zip Homepage
• 7-Zip Zstandard Homepage
• Request for inclusion into the mainline 7-Zip:
  • result, will currently not included :(
• p7zip Homepage - for Linux and MacOS with LZ4 and Zstandard

You find this project useful, maybe you consider a donation ;-)

• 7-Zip ZS Version 25.01 - Release 4
  • Brotli Version 1.2.0
  • Fast LZMA2 Version 1.0.1
  • Lizard Version 2.1
  • LZ4 Version 1.10.0
  • LZ5 Version 1.5
  • Zstandard Version 1.5.7

/TR 2026-01-10

• if you want an code signed installer, you need to donate sth.