We want to use 7Zip to extract the contents of the ISO file in our paid product. There is no other API free library available as of now that can unzip ISO files on all Windows platforms that we want to target. PowerShell trick does not work on Windows Server 2K8 R2. I have tries all the other options.

Here is the licensing info for 7Zip: https://www.7-zip.org/license.txt

It clearly says "Redistributions in binary form must reproduce related license information from this file." which seems to suggest that I can redistribute it and that is what PeaZip (another open source tool) seems to be doing as well.

My question is if I include the pre-built 7Zip.exe and 7Zip.dll binaries in my product's installer then does that mean that we must make our product open source as well?? Can it remain CLOSED source?

How does addition of these other two licensing restrictions (LGPL & BSD 3-clause License and unRAR liencesing restriction) affect our scenario? We will not be using the binaries for doing any 7Z or RAR compression decompression all we want is a way to extract contents of ISO file.

2 Answers 2


The relevant license for your use case is the LGPL license. The BSD license and the unRAR restriction only apply when you take the relevant portions of code out of the 7Zip sources.

A library or executable that is licensed under the LGPL can be used in a closed source application under the condition that it is possible for users of the application to replace the LGPL portions with a version of their own.


It is just a tool you are using. Ship it just the way you got it (binaries, documentation) and mention somewhere that you are using that tool, where it is found in whatever you ship, what changes you made --if any--, where to get the original, upstream version). The unrar license mostly says you are not allowed to base a compression program compatible with it by studying unrar's source, so I assume you are in the clear.

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