Upgrade Kali Linux 2019.x to Kali Linux 2020.x

For all existing installation of Kali Linux rolling release, you can always do a quick update. But first, ensure you have the official Kali repositories enabled.

sudo tee /etc/apt/sources.list<<EOF
deb http://http.kali.org/kali kali-rolling main non-free contrib
EOF

Take note of the current release.

$ cat /etc/os-release
PRETTY_NAME="Kali GNU/Linux Rolling"
NAME="Kali GNU/Linux"
ID=kali
VERSION="2019.4"
VERSION_ID="2019.4"
VERSION_CODENAME="kali-rolling"
ID_LIKE=debian
ANSI_COLOR="1;31"
HOME_URL="https://www.kali.org/"
SUPPORT_URL="https://forums.kali.org/"
BUG_REPORT_URL="https://bugs.kali.org/"

Then perform a full upgrade.

sudo apt update
sudo apt -y full-upgrade

Reboot system after upgrade

sudo reboot -f

Recheck your OS release.

$ cat /etc/os-release 
PRETTY_NAME="Kali GNU/Linux Rolling"
NAME="Kali GNU/Linux"
ID=kali
VERSION="2020.1"
VERSION_ID="2020.1"
VERSION_CODENAME="kali-rolling"
ID_LIKE=debian
ANSI_COLOR="1;31"
HOME_URL="https://www.kali.org/"
SUPPORT_URL="https://forums.kali.org/"
BUG_REPORT_URL="https://bugs.kali.org/"