Hello,
 
I was running my pgadmin4 v2 on my ipv6-only subnet using docker image. After the update, I noticed, that you have changed your webserver from Apache to gunicorn, and it is configured to listen only on ipv4 network (0.0.0.0), so it is unreachable from my network without using docker-proxy (and I can't use that on my configuration).
 
Please, consider switching to dual-stack networking in your configuration. It is just as simple as changing '--bind 0.0.0.0:${PGADMIN_LISTEN_PORT:-443}' to '--bind [::]:${PGADMIN_LISTEN_PORT:-443}' in your pkg/docker/entrypoint.sh.
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