git grep <previous-release-name> (e.g. jessie when stretch was released) and check if anything needs to be updated.testing, e.g. by calling git grep -E 'https?://[^ ]*testing[^ ]*'git grep -E 'https?://[^ ]*stable[^ ]*' | egrep -o 'https?://[^ ]*stable[^ ]*' | sort -u | while read URL ; do HEAD "$URL" | fgrep -q "200 OK" || echo $URL no more returns 200 OK.; donefor i in $(git grep -hEo 'https://packages.debian.org/de/stable/[-a-z0-9+]+' | sed -e s/stable/testing/) ; do echo -n $i" = "; GET -SUsed $i | fgrep Title; done | fgrep "Debian -- Error"git grep <eol-release-name> (e.g. squeeze) and check if anything