Hi, User of kdenlive since 2009 or so, I can just say that kdenlive binaries need to be archived with the .kdenlive project. Old or new version will break the project in various ways or cause crashes in kdenlive. Sometimes one needs to update to get rid of bugs and crashes. I use Debian unstable and the kdenlive packages from there. In the old times the packages were not usable and I had to recompile mlt and kdenlive from git trees, but in the last few years they have been mostly ok. snapshots.debian.org will find any old packages if upgrading kdenlive breaks something important.
Cheers, -Mikko