Last month RHEL 4.8 was released (see release notes). With this release RHEL 4 is entering phase 2 of it’s life cycle. During this phase only urgent software updates will be done and important or critical security issues will be handled.
During the Production 2 life cycle phase, at a minimum, qualified security errata of important or critical impact, as well as, urgent priority bug-fix errata may be released independent of minor releases.
If available, refreshed hardware enablement that does not require substantial software changes may be provided at the discretion of Red Hat via minor releases. New software functionality is not available during this phase. All available and qualified errata will be provided via the minor releases. The focus for minor releases during this life cycle phase lies on resolving defects with a minimum priority of high.
Updated install images will only be provided for minor releases during the Production 2 life cycle phase if required due to installer changes at Red Hat’s discretion.
Regrading RHEL 4, it seems the the release of 4.9 somewhere around Q1 2010, will end the 2nd phase, and the start of the 3rd one. It in the 3rd phase no new hardware is supported, and only mission critical bugs fixes are done. Security bug fixes has the same police like the second phase.
If you’re running RHEL version prior to version 4, notice that RHEL 2.1 just finished it’s 7 years life cycle on may 31st, and RHEL 3 will end it’s life cycle in October 31st, 2010. Details are available at Red Hat Enterprise Linux Life Cycle page.