First failure: https://travis-ci.org/JuliaRobotics/RigidBodySim.jl/jobs/583088525#L541-L548 Possibly related to https://github.com/JuliaDiffEq/DiffEqCallbacks.jl/commit/46cd2b256a943957d21a857da4b22b37833d8f6d, though there have been builds with version 2.8.0 of DiffEqCallbacks that passed.