Can I run Calibre 3.x and 7.9 on the same library?
To give some context, I have a couple of computers running Windows 10, but I also have an old laptop with Windows 7. I haven't updated Calibre in several years because newer versions won't work with Win 7.
I keep Calibre Portable and all my libraries on an external hard drive. I would love to be able to upgrade Calibre to the latest version, but that would prevent it from running on that old laptop.
I just came up with the idea of keeping a backup copy of Calibre 3 portable in a different location, then if I need to run it on the Windows 7 laptop I would run that version. Yes, I'm okay with the fact that it won't remember the library if I point it to one not inside the Calibre 3 portable folder. This is a "just in case" situation so I don't mind having to jump through hoops to get it to work.
My main question is whether running the new Calibre will make any changes to the libraries that will prevent me from running Calibre 3 on it.
If this is a Really Bad Idea
that's fine. That old laptop is just for emergencies anyway. I'm just trying to figure out my options before I upgrade Calibre.