@stefano:/etc/cron.daily$ crontab -l
no crontab for stefano
# crontab -l
no crontab for root

2017-02-05 12:42:42,835 INFO Initial blacklisted packages:
2017-02-05 12:42:42,866 INFO Initial whitelisted packages:
2017-02-05 12:42:42,868 INFO Starting unattended upgrades script
2017-02-05 12:42:42,870 INFO Allowed origins are: ['o=Debian,n=jessie', 'o=Debian,n=jessie-updates', 'o=Debian,n=jessie-backports', 'origin=Debian,codename=jessie,label=Debian-Security']
2017-02-05 12:43:15,848 INFO No packages found that can be upgraded unattended

APT::Periodic::Update-Package-Lists "1";
APT::Periodic::Unattended-Upgrade "1";

dpkg-reconfigure -plow unattended-upgrades

Applying updates on a frequent basis is an important part of keeping
 systems secure. By default, updates need to be applied manually using
 package management tools.

 Alternatively, you can choose to have this system automatically download
 and install security updates.

     Automatically download and install stable updates?

APT::Periodic::Update-Package-Lists "0";
APT::Periodic::Unattended-Upgrade "0";

APT::Periodic::Update-Package-Lists "7";
APT::Periodic::Unattended-Upgrade "1";

cat /etc/anacrontab
# /etc/anacrontab: configuration file for anacron

# See anacron(8) and anacrontab(5) for details.

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
HOME=/root
LOGNAME=root

# These replace cron's entries
1   5   cron.daily  run-parts --report /etc/cron.daily
7   10  cron.weekly run-parts --report /etc/cron.weekly
@monthly    15  cron.monthly    run-parts --report /etc/cron.monthly