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You are unable to install or update multilib package. Yum gives the error: Protected multilib versions: package-2.x86_64 != package-1.i686
Multilib means support for multiple architectures. This issue arises when .x86_64 and .i686 packages are not the same version. If both the 64 bit and the 32 bit version of a package are available in the repository, they must be the same version.
-Red Hat KB 2801851