From the Makes Sense On a Server dept.:
...Red Hat. The company has just announced that it is extending the production lifecycle of Red Hat Enterprise Linux (RHEL) 5 and 6 from seven to 10 years in response to enterprise customer demand and Red Hat???s hardware original equipment manufacturer (OEM) partners.

For any company, upgrading to a new version of an operating system requires detailed advance planning. Red Hat has extended the Red Hat Enterprise Linux lifecycle so customers can remain on their current version longer. With the new Red Hat Enterprise Linux lifecycle, customers will benefit from continued feature enhancements while Red Hat???s application binary interface (ABI) and application programming interface (API) compatibility for their existing application.