[5] The latest version requires Mac OS X Lion or higher.

[6] Prior to the purchase by MacPaw in 2017,[7] The Unarchiver was previously free software licensed under the LGPL, up to version 3.11.1 (released 2016).

[10][11] The corresponding command line utilities unar and lsar are free software licensed under the LGPL[12][13] run on Microsoft Windows, Linux, and macOS.

[14] A main feature of the Unarchiver is its ability to handle many old or obscure formats like StuffIt as well as AmigaOS disk images and LZH / LZX archives, and so on.

This is credited in its source code to the use of libxad, an Amiga file format library.