what’s the current version of krakatoa? The download for eval is 1.5 but the online docs refer to 1.6 – you get that if you purchase?
Yes and no, kind of 
The current commercial version is 1.5.1 and the Evaluation version is the same build minus the license.
As the documentation states on the TOC page,
But anyone who buys a Krakatoa license and the mandatory support contract for the first year is entitled to Beta-testing whatever we are developing at the moment.
A version labeled 1.5.2 is being beta tested but will be released later this year as 1.6.0. If you buy a license now and want to try out the current Beta (which is quite stable as we use it in production, but has some kinks that still need attention), we will let you download the latest builds. There are still some amazing speed ups we got this week that even our current beta testers haven’t see yet, so we are quite excited about it… 
EDIT: Ooops, I saw your support email, I will answer it separately.
You caught us in a transitional moment where we updated the documentation so all existing customers beta-testing it can follow the changes we are making.
I am sorry you had a bad experience, but there were technical reasons we could not keep both documentation versions online.
It was my fault and I will try to help with whatever I can - feel free to use the support address or this forum with whatever questions you have and I will try to answer as fast as I can.
Thanks very much Borislav, it’s making sense now.