The final version of Rhino 6 has just come out, but you should do a little more clarity and order.
There is a final version of Rhino 6, then there is an SR release candidate 1, then there will be a second RC …
Along with these there is a wip of Rhino 7 (a version that you do not understand on the site, you can hardly notice, version of 17/01/2018, but if you click the date shown is different: 12/01/2018) .
All this causes confusion and gives the sense of a Rhino, yes in evolution, but precarious, never with a finished version (in the sense not complete, but stable, of course).