you can already do this, you'll need to make some modifications
- install mail as described in section 4.8 of this manual
2.enable the Pi-hole update in /etc/cron.d/pihole (uncomment line 22) - modify /opt/pihole/update.sh (these modification will solve the "command not found" errors)
line 82: piholeVersion=$(**/etc/.pihole/pihole -v -p -c)
line 83: piholeVersionLatest=$(/etc/.pihole/pihole -v -p -l)
line 85: webVersion=$(/etc/.pihole/pihole -v -a -c)
line 86: webVersionLatest=$(/etc/.pihole/**pihole -v -a -l)
you will get a weekly mail, see below:
To: root
Subject: Cron root@raspberrypi /usr/local/bin/pihole updatePihole
::: Checking for updates...
:::
::: Pi-hole version is v2.9.5 (Latest version is v2.9.5)
::: Web Admin version is v1.4.4.2 (Latest version is v1.4.4.2)
:::
::: Everything is up to date!