Upravte soubor "/etc/apt/sources.list"
deb http://ftp.cz.debian.org/debian/ jessie main deb http://security.debian.org/ jessie/updates main deb http://ftp.cz.debian.org/debian/ jessie-updates main deb http://ftp.debian.org/debian jessie-backports main deb http://packages.dotdeb.org jessie all
A přidejte klíč pro www.dotdeb.org
wget https://www.dotdeb.org/dotdeb.gpg apt-key add dotdeb.gpg