Converseen, being created using open-source frameworks and libraries such as Qt and ImageMagick, is available for free for several operating systems including Windows 7/8/10/11, all versions of Linux such as Ubuntu, Mint, Fedora, Arch Linux, openSUSE either through the official repos or through AppImage, Snap and Flatpak packages, macOS 10.13+, but also FreeBSD.
You can also download or fork code from SourceForge or GitHub.