first I downloaded the original libbonobo and libbonobo-devel files.
then I installed them with
# rpm -ivh --force libbonobo*
then I checked which versions are installed
# rpm -qa |grep libbonobo
it listed me all the rpm's with this name. I saw the old and new ones sitting together, so I had to uninstall the new-version ones.
# rpm -e libbonobo-<version number> libbonobo-devel-<version number>
after that for a double check I did the rpm -qa again to see if the old version is safely there. and it was
so rather then uninstalling the new version, then installing the old one, I switched the order
I don't know of any other way of downgrading an rpm