I'm very disappointed. Of course i wrote to Xicat manifesting my disappointment, but i don't think they will answer. Doesn't matter if i own a previous version of the game, i'm not eligible for an upgrade at a cheaper price than the full version. Also because i downloaded the 6.xx demo and it is quite identical to the 5.xx version, couldn't see much changes. Probably it is faster, the GUI is improved, but i don't think that's enough for asking to buy it again.
Business is business, but it can be done in many ways.
But, of course, this is only my opinion.