An anonymous reader writes "Linux distributions track upstream projects, releasing a particular version with each official release. But how far behind the latest versions do these releases linger? Scott Shawcroft did an interesting new study into this relationship between distributions and upstream projects. Shawcroft says: 'Over the last 10 months I've been working on Linux evolution research. Similar to distrowatch, I track the current versions of packages in a number of distributions and the current upstream version. Based on that data I then graph a number of metrics to understand the relationship between upstream and downstream.' His presentation on the topic scheduled for [this] week's open source convention, OSCON, should provide an interesting insight into that relationship. Currently he is tracking 20 projects including the Linux kernel, Firefox, GCC, OpenSSH and GNOME on Arch, Debian, Fedora, Gentoo, openSUSE, Sabayon, Slackware, and Ubuntu."