From release 2.7.0 we now keep a static copy of the documentation for dotNetRDF on this site. This makes it easier to find the documentation for a specific release and will make it easier for us to release documentation for the upcoming 3.0 preview releases without overwriting the documentation for the stable 2.x release.
Currently each minor release has its own sub-directory beneath here - there are no direct links between versions.
The documentation for the current stable version is always accessible here.
The bleeding-edge documentation is always accessible here
The current STABLE version is 2.7.x