The current stable version is 6.10.7. It is very stable at this point.

Next release will be 6.11.0 which will include a few new features like webmentions support.

Most of our efforts, though, are now focused on b2evolution v7. An alpha version is already out but the next release will include an all new "Quick start wizard" which should make it easier to get started with a setup that matches the user’s needs, rather than a default demo setup.