From time to time, Red Hat issues updated packages that correct functional or security-related problems with released packages. You can use Red Hat Network to obtain and install updated packages. However, if you prefer, you can download updated packages via FTP and install them using the rpm command. Red Hat makes updated packages available on the public FTP servers ftp.redhat.com and updates.redhat.com.
To install an updated package, use the -F flag, which stands for freshen. For instance, to install an updated version of the gnupg package, issue the command:
rpm -Fvh gnupg-1.2.1-10.i386.rpm
By specifying -F rather than -U, you instruct RPM to install the updated package only if an earlier version of the package is already present. This lets you use wildcards to specify entire sets of updated packages:
rpm -Fvh *.rpm
This command will not install packages that aren't already installed. But, it will install updated versions of any existing packages.