Просто запусти в терминале sudo sed -i -r 's/([a-z]{2}.)?archive.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list and sudo sed -i -r 's/security.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list sudo apt update
sudo apt upgrade
Просто запусти в терминале
sudo sed -i -r 's/([a-z]{2}.)?archive.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list
and
sudo sed -i -r 's/security.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list
sudo apt update
sudo apt upgrade