Quick update. Invaders are now implemented, using the Aether Rifts described in the change log. I'm going to set up a new campaign to test them, as I have made some other NPR changes as well.
It will likely be a week or two before the next release so I have time to do that testing. There are no game-breaking bugs in 1.9.5, at least so far. The worst is the 'all roads lead to Sol' bug in Random Stars and that does have a semi-workaround.