Comment 2 for bug 2069006

1) I do not provide support for people using distro provided packages. If
you are using a distro provided package, uninstall it and install the
official calibre binary from https://calibre-ebook.com/download_linux

2) It doesn't fail for me using my legacy version of Calibre Companion
running calibre 7.12 on Windows 10. I don't have a koreader installation
to test. If this problem isn't fixed by running the official calibre
binary then someone with koreader will need to look at the problem
and provide repeatable debugging information.