Red Hat Knowledgebase

Yes, the up2date utility can be used to upgrade your kernel. Updating a kernel is never completely without risk, but the method up2date uses will always leave your current (running) kernel on the system so you can go back to it if disaster strikes. The recommended method of updating your kernel is:

(Uniprocessor kernel)
# up2date -f kernel

(Update entire system, including all kernels)
# up2date -fui

More thought and planning needs to go into kernel updates if you are using either the kernel-unsupported package or 3rd party drivers not available from Red Hat. Read any release notes to see if Red Hat changed any module names and edit the /etc/modules.conf appropriately prior to running up2date.