sudo vi /etc/apt/sources.list

将所有句子中的“http://archive.ubuntu.com/ubuntu/”更改为“http://old-releases.ubuntu.com/ubuntu/”

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://old-releases.ubuntu.com/ubuntu mantic main restricted
# deb-src http://old-releases.ubuntu.com/ubuntu lunar main restricted

# Major bug fix updates produced after the final release of the
# distribution.
deb http://old-releases.ubuntu.com/ubuntu mantic-updates main restricted
# deb-src http://old-releases.ubuntu.com/ubuntu lunar-updates main restricted

# N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
# team. Also, please note that software in universe WILL NOT receive any
# review or updates from the Ubuntu security team.
deb http://old-releases.ubuntu.com/ubuntu mantic universe
# deb-src http://old-releases.ubuntu.com/ubuntu lunar universe
deb http://old-releases.ubuntu.com/ubuntu mantic-updates universe
# deb-src http://old-releases.ubuntu.com/ubuntu lunar-updates universe

# N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
# team, and may not be under a free licence. Please satisfy yourself as to
# your rights to use the software. Also, please note that software in
# multiverse WILL NOT receive any review or updates from the Ubuntu
# security team.
deb http://old-releases.ubuntu.com/ubuntu mantic multiverse
# deb-src http://old-releases.ubuntu.com/ubuntu lunar multiverse
deb http://old-releases.ubuntu.com/ubuntu mantic-updates multiverse
# deb-src http://old-releases.ubuntu.com/ubuntu lunar-updates multiverse

# N.B. software from this repository may not have been tested as
# extensively as that contained in the main release, although it includes
# newer versions of some applications which may provide useful features.
# Also, please note that software in backports WILL NOT receive any review
# or updates from the Ubuntu security team.
deb http://old-releases.ubuntu.com/ubuntu mantic-backports main restricted universe multiverse
# deb-src http://old-releases.ubuntu.com/ubuntu lunar-backports main restricted universe multiverse

sudo apt update
sudo apt upgrade
sudo do-release-upgrade