Download it from http://www.dokeos.com/download/dokeos-1.8.6-beta2.zip
This time, we are quite sure it will be the last beta. The RC1 should be out before the end of February.
There are still little bugs in documents edition and upload, as well as in exercises, but these are all minor bugs in comparison to what one could find in Dokeos 1.8.5.
There are loooooads of new features (really, I mean it) – make sure you check the administration panel to activate some of them (the big ones). I really intend to consider this one as a pseudo-stable release that will not imply any database change in the future, so it can be used in pre-production environment.