The final version of Fedora 9 was initially planned for next week, but the release has been put back by two weeks to May 13, according to the Fedora Project.
Among the updates to Fedora 9 are improvements to the Xen hypervisor, support for new file systems, and the inclusion of newer versions of the Firefox browser and the KDE desktop environment.
"This is the most critical release for the Fedora community to use and test and report bugs on," Red Hat's Jesse Keating said in a release announcement.
Red Hat initially released the preview as a BitTorrent download, and it is planning direct HTTP downloads for this week. Users can choose from Live images--which execute from a disc, without the need to install--or standard CD or DVD installers.
The final version is also scheduled to include the recently released Linux 2.6.25 kernel. A release candidate is also scheduled for May 1, but it is primarily for a smaller group of testers.
Among the new features are improvements to the Xen virtualization hypervisor, the addition of support for the ext4 file system and encrypted file systems, and upgrades to Firefox 3 and KDE 4.0.
In March, Red Hat released new beta versions of its enterprise and desktop Linux products, with improvements including better virtualization and clustering features, to make the operating system a more stable platform for server farms.
Red Hat Enterprise Linux (RHEL) 5.2 beta upgraded the core virtualization hypervisor, Xen, to Xen 3.1.2, and allowed support for up to 64 processors per system and up to 512GB of memory per server. The Numa (nonuniform memory access) interface was also improved.
Some users have criticized Red Hat for neglecting its freely available distribution while focusing on its more profitable enterprise version. In February of last year, Eric Raymond, a key figure in the open-source community, transferred his allegiance from Fedora to Ubuntu. At the time, he cited issues such as "chronic governance problems," problems with maintaining repositories, "effectively abandoning the struggle for desktop market share," and "failure to address the problem of proprietary multimedia formats."
Matthew Broersma of ZDNet UK reported from London. ZDNet UK's Peter Judge contributed to this report.