Kaidan linked against old library
/usr/bin/kaidan is linked against libZXing.so.1, which was part of package zxing-cpp. However, with new version of zxing-cpp (I am running 2.0.0-1), the libZXing.so.1 is not available anymore and thus Kaidan crashes.
Kaidan needs to be rebuilt to be linked against new version of library (libZXing.so.3), but needs to be also patched to be compatible with new API (I can't send MR here for some reason, but one can easily take same patches like Arch AUR version: https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=kaidan). Rebuilding Kaidan with patches included in AUR repository fixes problem for me.