In testing a new version of a package, I'd like to be able to switch
between older and newer versions without having to repeatedly download
either one. Yum can update using local RPMs with the localupdate
option, but I don't see anything like a localdowngrade option. Is there
another way to do this (other than erase and localinstall)? I'm asking
because
http://illiterat.livejournal.com/7834.html
claims that "there are no known reasons to use rpm instead of yum".