Apple releases an update on the USB-C Digital AV Multiport Adapter-- now offering a USB-C port, HDMI port and USB-A port together with support for HDMI 2.0, allowing it to handle 4K video at 60Hz.
The updated version (model number A2119) retains the same dimensions as the first (model A1621), and can handle video MacBook Pro (introduced in 2017 or later), Retina iMac (from 2017 or later), iMac Pro and iPad Pro models. The Mac needs to be running macOS Mojave 10.14.6 or later, while the iPad needs to be running iOS 12.4 or later.