Today, Red Hat released its “service pack” or “maintenance release” of RHEL4. According to Red Hats life cycle policy” it ends the production stage two.
That means: In future only bugs with a high severity will be fixed. The “normal” life cycle of RHEL4 will end in approx. one year.
This means that everyone using RHEL4 systems should think about a migration scenario to RHEL6. Unfortunately, Red Hat does not support OS upgrades, you need to install the systems from scratch. Since RHEL4 was released in February 2005, most of this systems have reached there lifecycle anyway.
Its time to migrate your RHEL4 systems.
For the release notes, please see http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/4/html/4.9_Release_Notes/index.html
Have fun with migrating….