Download the [https://www.avrfreaks.net/sites/default/files/forum_attachments/AtmelICE-kext-for-High-Sierra.zip](AtmelICE kernel extension).
sudo chown -R root:wheel AtmelICE.kext
sudo mv AtmelICE.kext /Library/Extensions/AtmelICE.kext
sudo find /Library/Extensions/AtmelICE.kext/ -print0 | sudo xargs -0 xattr -c
sudo kextload /Library/Extensions/AtmelICE.kext
Open System Preferences and allow the kernel extension from "Nicholas Sayer".
$ system_profiler SPUSBDataType
should show "Atmel-ICE CMSIS-DAP".
ATtiny 1614 uses UDPI