Old bettercap Update: This tutorial is up-to-date for last kali version 2020.1
Donwgrade instructions
If you have chosen the legacy deb package, follow this instructions to install it:
Requirements: wget
Uninstall latest 2.x bettercap package
~# apt remove bettercap
Install the ruby dependencies
~# apt install ruby-packetfu ruby-colorize ruby-net-dns ruby-em-proxy
Install dpkg -i ruby-network-interface_0.0.1-0kali1+b1_amd64.deb
Install dpkg -i ruby-rubydns_1.0.3-0kali1_all.deb
Install dpkg -i bettercap_1.6.2-0parrot1_all.deb
Additionally, you may want as optional to mark the package as "hold" to avoid its update in order to keep the downgraded compatible version:
~# apt-mark hold bettercap Important note. This downgrade method was tested only on Kali and Parrot Security Linux.