I thought I give PD15 a try and upgraded today on Mojave 10.14.6: - Unfortunately nothing is working the way it should. The parallels hypervisor is still slow as hell, so I reverted back to Apple's hypervisor. - The main problem point however is that Windows was completely unusable as soon as I plugged in the external HDMI monitor as a second screen. Windows simply froze each time I tried this (and yes, I had tried ALL monitor settings in PD like Best for Retina (my default setting), Scaled or Best for external displays). - PD15 is missing the Direct X version selector, so nothing could be changed there. - I also tried various settings with display spaces etc, nothing helped to let Windows operate normally. As soon as I plugged in the secondary monitor, Windows each time simply froze (mouse was still movable), but didn't accept any further inputs. And yes, of course the parallels tools were updated, so no error from user side. I reverted back to PD14 until Parallels fixes this. This was simply another disaster upgrade.