The paper “The future is not always open“, co-authored by James Grant, Michael Kunzinger (Vienna), Clemens Sämann (Vienna), and Roland Steinbauer (Vienna), has been published in Letters in Mathematical Physics. The paper demonstrates the breakdown of several fundamentals of Lorentzian causality theory in low regularity. A link to the published version is here. The diagram below collects the (non)-implications between the causal regularity properties studied in the paper.