In /var/log/dmesg on Ubuntu 20.04 LTS
apparently filtering via arp/ip/ip6tables is no longer available by default and so an update your scripts is required to load br_netfilter if Cloudron need this.
Thanks for the heads up. We don't really use any of these tools but something to keep in mind. We do use ipset for the firewall block list, but it seems to work fine with Ubuntu 20 though.