The CentOS developers have announced the availability of version 5.5 of their free Linux distribution. CentOS 5.5 is based on Red Hat Enterprise Linux 5.5 (RHEL), which was released at the end of March, and includes a number of bug fixes, updates and new functionality.

More details about the release can be found in the release notes and in the RHEL 5.5 upstream release notes. CentOS 5.5 is available to download for i386 and x86-64 architectures, either as multiple CD ISO image files or as one or two DVD ISO images.

How to upgrade?
If you are already running CentOS-5.4 or an older CentOS-5 distro, all
you need to do is update your machine via yum by running :
'yum update'
Running 'yum list updates' before doing the update is recommended, so
you can get a list of packages that are going to be updated. To check
you are indeed on CentOS-5.5, run : 'rpm -q centos-release' and that
should return: 'centos-release-5-5.el5.centos'