We are in the process of testing out the new CentOS release on our servers. So far this is all going very well, and we expect to be upgrading all of the servers running CentOS 7 to CentOS 7.4.1708 over the next week. We do not expect anyone to see any issues with this other than a brief outage to reboot the individual VPS servers. These outages should last a few minutes at most, although at some time we will also be scheduling some more hardwar reboots of physical servers that WILL have a longer downtime.
CentOS 7.4 includes a number of improvements, and re-basing of some of the packages.