N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Do you want to accept these changes and continue updating from this repository? [y/N]

A simple fix for this is to either:

Run the following and manually answer y when asked to confirm the relevant changes
Note: this is NOT apt-get, but rather just standalone apt

sudo apt update

Run apt-get update with the --allow-releaseinfo-change flag to automatically confirm the changes for you:

sudo apt-get update --allow-releaseinfo-change

Installation package

dpkg -i <package.deb>

Info package

apt-cache show <package>
dpkg --print-avail PACKAGE_NAME

Fix broken package

apt-get -f install <package>

Quel repository a installé le package : spécifique, priorité, ...

apt-cache policy <package

Quel package a installé un fichier :

dpkg -S <filename>
dlocate <filename>

Quel package installé utilise <packagename>

apt-cache rdepends --installed <packagename>

Lister les packages qui prennent le plus d'espace

dpkg-query -Wf '${Installed-Size}\t${Package}\n' | sort -n

Nettoyer /var/apt/cache

sudo apt-get clean

Marquer un paquet en auto

apt-mark auto python-matplotlib-data

lister les versions disponibles dans APT

apt-cache madison zabbix