Supporting CC-BY-SA 3.0


Sven Vermeulen Tue 29 November 2011

Until now, documents on the Gentoo website all had to be licensed under the Creative Commons Attribution/Share Alike license, version 2.5. Why? Because at the time of the license choice, that was probably the latest version at hand. In the XML code itself, the license tagging was done using a <license /> tag. Simple and efficient. But things change, and so do license versions.

The folks over at Creative Commons have released version 3.0 somewhere in 2007. I'm not going to cover the differences here, but in general, the principle behind Gentoo's choice for the CC-BY-SA license remains. But we didn't change our licenses and there was no real need for it either.

Recently however, the Official Gentoo Wiki was announced, which uses the CC-BY-SA license as well... but the 3.0 version of it. You can't blame them for taking the latest version, but that does made it a bit more difficult to share resources between the two repositories (wiki versus GuideXML-ified website). The solution? Support CC-BY-SA 3.0 for GuideXML too.

A few commits in our repository made that change happen. Nothing big though: the DTD is updated to allow for <license version="3.0"/> tags, the XSL is updated to support this attribute (and display the new license) and a few other files (supporting files, like the GuideXML Guide) have received the necessary updates.

The result of the change is that existing documents remain under the current 2.5 license (we are not allowed to bump versions of licenses as most documents are not copyrighted by Gentoo Foundation but by their respective authors) but new documents can now use the 3.0 license.

Edit: Sebastian Pipping mailed me to say that in the legal code of the CC-BY-SA 2.5 license there is a clausule about "... a later version of this license with the same License elements...", so perhaps I might have a "take two" on this.