The Oovcde web site is at http://oovcde.sourceforge.net.
The description lists the features added in each version.
The features shows a current list of functionality.
Information about diagrams is described in the design document.
Release notes can be seen under "Code" in trunk/docs/releaseNotes.txt, but
are notes about the work under development. Use the history to see notes
that match a particular version.
The Linux version requires GTK3.