Usually, you want to use the last version of the operating system and if it is true you will update your OS early or later. In this article, you can found a simple and small instruction to update Centos 7 from 7.x to the latest version (now it is 7.4) See CentOS 7.4 release note for more information about changes.
Check the current version
# cat /etc/redhat-release CentOS Linux release 7.3.1611 (Core)
Upgrading is the same as the update option with
Before upgrading purge all old cache and download a new one.
And next, you can upgrade OS.
yum clean all yum makecache yum -y upgrade
Below is described info that I got (I left only main info)
# yum clean all ... Cleaning up everything Cleaning up list of fastest mirrors # yum makecache ... Metadata Cache Created # yum -y upgrade ... Complete!
After the upgrade process has completed seeing changes reboot a system
And repeat to check the current version of the system
# cat /etc/redhat-release CentOS Linux release 7.4.1708 (Core)
Of course, don’t do this procedure on a system with users.