Hi Vicki,
Go to the site indicated above. That is the official version.
Our experience:
6.0.09 initially caused huge problems with rx screens, very very very slow, solved by turning hardware acceleration off (and by buying video cards and new laptops.....)
This also had problems with some of the MU numbers, I think it had to do with the denominator (??) in some of the MU calculations.
6.0.10 installed easily, fixed the MU problems, we attested on this version. I don't remember that much more about it, because I think 6.1.1 followed relatively soon.
6.1.1 did well initially, but after several months got pretty buggy, some problems with forwarding messages, increasingly frequent crashes, etc. AC tech support said to upgrade to 6.1.2
We have been on 6.1.2 for several months. Sending orders is a little slow, but otherwise this release is rock solid (at least as rock solid as any Windows program can be.)
I would go right to 6.1.2
(I am not absolutely guaranteeing any of the above info, to an extent the whole last 9 months has been a bit of a blur.)
Hope this helps! Gene