I don’t agree with the prerequisite of “doesn’t have a maintained version” because I don’t feel like that makes a difference with the premise of specifically running older software, whether it has a new version available or not.
But anyways… I will try to adhere to that anyways, and use Ubuntu as an example as that’s what I use.
7yuv: This and every Qt4 app for example no longer runs because Ubuntu 20.04 and above (and probably many other distros) does not provide it anymore. 7yuv is still available for download, but has not been updated, and does not run on my current 22.04 box.
Dia: Same story here. No longer developed. The remaining binary deb package was built for Ubuntu 12.04 and no longer runs due to a dependency on libpng12 (the current version is 16). Yes I could possibly recompile from source if the API hasn’t changed, but the discussion was specifically about running older binaries.