We have not planned a specific date, really when we consider there're enough changes we do a release. Are you interested in some specific fixed bug or feature, because you can currently replace your OpenKM.war file with a 6.3.10 build without issues, the upgrade process is described here
https://docs.openkm.com/kcenter/view/ok ... -6310.html and we are not doing radical changes in the code ( I'm talking about database changes ), that means there's no danger in the upgrade.