More recent data and simulations of "Milkomeda", the collision of the Milky Way and Andromeda galaxies?
Since the second data release (DR2) of the European Space Agency's Gaia mission there has been a revolution in astrometry, including measuring the motion of the Andromeda Galaxy.

On February this year van der Marel et al (also in ArXiv) published interesting results on that matter by using Gaia's DR2 measurements. The results reveal that the collision is going to happen 600 million years later than the previous estimate (in 4.5 Gyr instead of 3.9 Gyr). Also Andromeda appears to have more tangential motion than previously thought and thus "the galaxy is likely to deliver more of a glancing blow to the Milky Way than a head-on collision".

Also interesting, M33 (Triangulum galaxy) is going to make its first infall towards Andromeda and might interact gravitationally quite a lot with it. The absence of stellar streams between Triangulum and Andromeda show that this is the first time they are going to meet each other.

Thanks to Gaia the measurements are now so precise that for the first time we are able to notice even the minute rotation of both Triangulum and Andromeda galaxies astrometrically (and not only by using doppler shifts).