Here, #lpinfo -m | grep -E "PDF|pdf" returns nothing. #lpinfo -m returns none of the files from /usr/share/ppd/cupsfilters
This is my /etc/apt/sources.list, I am updating three or four times a year: deb http://ftp.uni-erlangen.de/debian/ stretch main deb-src http://ftp.uni-erlangen.de/debian/ stretch main deb http://ftp.uni-erlangen.de/debian/ stable main deb-src http://ftp.uni-erlangen.de/debian/ stable main deb http://security.debian.org/ stable/updates main deb-src http://security.debian.org/ stable/updates main deb http://security.debian.org/ stretch/updates main deb-src http://security.debian.org/ stretch/updates main deb http://ftp.uni-erlangen.de/debian/ stretch-updates main deb-src http://ftp.uni-erlangen.de/debian/ stretch-updates main deb http://dl.bintray.com/tvheadend/ubuntu stable main # I need this line for scilab: deb http://ftp.uni-erlangen.de/debian/ sid main