The Kunena team has announce the arrival of Kunena 7.0.4 [K 7.0.4] in stable which is now available for download as a native Joomla extension for J! 5.4.x/6.0.x. This version addresses most of the issues that were discovered in K 6.2 / K 6.3 / K 6.4 and issues discovered during the last development stages of K 7.0
This is for users to help other users, to discuss topics that are related to forum administration in general or problems in running Joomla. This is not the place to ask for Joomla support. If you want assistance with Joomla please ask at
forum.joomla.org
The solution is actually as simple as changing the site template so that you can use K 1.6 and you won't have to worry about trying to synch users across multiple domains or about adding bridging software (and all the attendant headaches that these can involve) and it only takes a relatively short amount of time to achieve a simple solution. But ... if you really have your heart set on using what you've got then I understand.