We are in the process of upgrading our EECS systems from CentOS 6 to CentOS 7, and hope to be done by fall 2017. It's important for us to do this because no new hardware support is being added to the aging CentOS 6. In addition, many of the new software packages that we need to install require the more updated libraries available in CentOS 7. CentOS 7 was released in 2014.
Most of the major changes between CentOS 6 and CentOS 7 are administrative ones that should have little effect on you. However, please test all of your applications extensively, and let us know of any problems that arise. Due to library version changes, you may need to recompile any software that you've compiled.
One major change you will notice is that we are changing the default window manager from Xfce to GNOME 3. GNOME 3 is bundled with CentOS 7. You can read more about GNOME 3 here.