Xtraction 2018.0 was pulled a couple of weeks ago, due to a recently discovered issue. 2017.2 is back to being the "current" release. As soon as this latest issue is fixed and included in 2018.1, 2018.1 will be released. The last estimate was late May/early June, but I don't know if the issue has been fixed or if a more definitive release date has been set. My guess would be sometime in June. But, that is all it is - a guess.
I guess the issue is worse than they originally thought, as it's mid June now
It is still possible it might release in June, but I wouldn't be surprised if it sneaks into July. Time flies when you're having fun.