Centos comes with kernel 3.10.0-514. This is not a problem securitywise, as RedHat patches security and some bug fixes into its distribution.
If you have nothing to lose but want to live on the bledding edge and want support for current hardware like dvb-tuners, then Elrepo is for you: Either long-term-support/lt or absolutly current kernels (mainline/ml) yum’ed directly to your server (and for years on mine with no issues). At the moment kernel 4.13.3 is current, within a day or two after release of kernel 4.14.0 a simple
yum --enablerepo=elrepo-kernel update should install it.
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm yum --enablerepo=elrepo-kernel install kernel-ml