The Pihole web interface tells you to run pihole -up to get the latest version. But if you are running pihole as a docker container we need to do it a little bit different.
To update pihole; Open a terminal and do the following:
Stop the container:
docker stop piholePull the latest Pihole
docker pull pihole/piholeRemove your existing pihole container
docker rm -f piholeStart container
#Depending on how you set it up you might run
./docker-run.sh
#or
docker run pihole/piholeAfter updating this the custom blacklist was still intact.