Please note that athough through the few tests we did, we cannot guarantee this tutorial will work, and we suggest you make a full backup of your data before proceeding.

CentOS 4 is a free version of RHEL 4, CentOS 4 is currently in RC1, and not suggested for production use yet. It sports a few new features, including support for the 2.6 kernel which yeilds much better performance on SMP and HT systems.

Lets get on to the tutorial now.

1. Backup your data.

2. Import GPG keys:
rpm --import http://beta.centos.org/centos/4.0beta/os/i386/RPM-GPG-KEY
rpm --import http://beta.centos.org/centos/4.0beta/os/i386/RPM-GPG-KEY-centos4.0beta

3. Install/Upgrade yum:
rpm -Uvh --nodeps http://beta.centos.org/centos/4.0beta/os/i386/CentOS/RPMS/yum-2.1.13-2.centos4.noarch.rpm

4. Upgrade the release:
rpm -Uvh http://beta.centos.org/centos/4.0beta/os/i386/CentOS/RPMS/centos-release-4.0beta-5.i386.rpm

5. Have yum update your OS:
yum upgrade

Notes: We have noted that you may receive some errors during the upgrade, we usually solved this by running yum upgrade or yum update a second time.

Similar Articles : Upgrading CentOS 3.3/3.4/3.* to CentOS 4, Upgrading Red Hat 9 to CentOS 3.4 or 4, Upgrading Fedora Core 1 or 2 to CentOS 3.4 or 4