Red Hat offers a 10-year lifecycle for RHEL, which includes the promise of Application Binary Interface (ABI) compatibility. As such, Red Hat will not change major elements of an in-production release in a way that could impact stability or existing compatibility. That doesn’t mean, however, that Red Hat can’t and doesn’t actually provide some new features to existing RHEL 6.x users.
“Red Hat Enterprise Linux 6.6 Beta does include some features that were first introduced with Red Hat Enterprise Linux 7 in June, the most prominent being Performance Co-Pilot (PCP),” Almy said.