Ubuntu 9.04 Receives EXT4 Support Written by Michael Larabel in Operating Systems on 11 January 2009 at 09:10 AM EST. Page 1 of 5. 25 Comments. With the EXT4 file-system having been stabilized with the Linux 2.6.28 kernel, the Ubuntu developers are preparing to adopt this evolutionary Linux file-system update. EXT4 will not replace EXT3 as the default file-system until at least Ubuntu 9.10, but as