Yep! That's exactly why. USB-C alternate mode only supports DisplayPort 1.3 and HDMI 1.4b. You'll need an active adapter like you mentioned. Not surprisingly, A

Yep! That's exactly why. USB-C alternate mode only supports DisplayPort 1.3 and HDMI 1.4b. You'll need an active adapter like you mentioned. Not surprisingly, Apple doesn't sell them, that would be to useful. For future readers, here's one as an example: https://www.amazon.com/dp/B01FIVSC6Y/ https://www.amazon.com/dp/B01FIVSC6Y/