It's been 16 1/2 months since the last release (6.31) and the next release (6.4x.x) seems to be right around the corner. It could still be another month away.

As to multi-player, having more than 4 players is sufficient and I've made several mentions to having an edition containing all pro features, except that you have to display the logo. Not having to display the logo is the most expensive part ($500+ from what I've read). If one wants to not display the logo, they should be able to just purchase that license separately. It doesn't require much adjustment either, just a small change in the license key.