pi-hole_bullseye_to_bookworm.txt

# In case you need your raspberry pi model:
cat /sys/firmware/devicetree/base/model

# See versions of raspbian/debian currently supported by pi-hole:
dig +short -t txt versions.pi-hole.net @ns1.pi-hole.nets.pi-hole.net @ns1.pi-hole.net
"Raspbian=10,11,12 Ubuntu=20,22,23,24 Debian=10,11,12 Fedora=39,40 CentOS=9"

# update packages on current OS version:
sudo apt-get update && sudo apt-get upgrade

# replace all instances of 'bullseye' with 'bookworm' in both of these:
sudo vim /etc/apt/sources.list
sudo vim /etc/apt/sources.list.d/raspi.list

# quick check of space left on partitions to ensure there is enough space for upgrade:
df -h

# Upgrade time (this will take ~20-30min on average):
sudo apt update && sudo apt full-upgrade

# copy/paste or take note of any error messages along the way (it could save your bacon)

# once finished, reboot the pi
sudo shutdown -r now

# make sure the service is running, and that you can access the web console and everything:
pihole status
  [✓] FTL is listening on port 53
     [✓] UDP (IPv4)
     [✓] TCP (IPv4)
     [✓] UDP (IPv6)
     [✓] TCP (IPv6)

  [✓] Pi-hole blocking is enabled

# Check 
# IF YOU'RE RUNNING UNBOUND AND DNS IS BEING WEIRD/FAILING, PLEASE DO THIS:
systemctl is-active unbound-resolvconf.service
sudo systemctl disable --now unbound-resolvconf.service
sudo sed -i 's\^unbound_conf=\#unbound_conf=\g' /etc/resolvconf.conf
sudo rm /etc/unbound/unbound.conf.d/resolvconf_resolvers.conf
sudo systemctl restart unbound.service
# (see https://discourse.pi-hole.net/t/warning-raspbian-october-2021-release-bullseye-unbound/51027/41 for more info on that)

# check to see the version changed:
cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 12 (bookworm)"
NAME="Raspbian GNU/Linux"
VERSION_ID="12"
VERSION="12 (bookworm)"
VERSION_CODENAME=bookworm
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"

# Clean up packages that are no longer needed
sudo apt-get autoremove