Version 5.6.8 is available. The only changes are several bug fixes. Saved games back to version 5.6.0 will probably work, but they will still be bugged, so it's best to start a new campaign.

The most serious bug fixed in this version was a problem with the Eastern Kingdoms that occurs when that faction bribes a settlement. I fixed the problem by removing their diplomats. If you want to continue a saved campaign from an earlier version there are instructions for killing off the Eastern Kingdoms here.