Guacamole: Change network bridge

After installing Guacamole via App Center, a new bridge is created in the system:

Kernel-IP-Routentabelle
Ziel            Router          Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.16.1.1      0.0.0.0         UG    0      0        0 eth0
172.16.0.0      0.0.0.0         255.255.255.0   U     0      0        0 br-e8927f351c60
172.16.1.0      0.0.0.0         255.255.255.0   U     0      0        0 eth0
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0

Unfortunately, I happen to use a 172.16.0.0/24 network (via router). Thus, the Univention server does not have any outside network connection.

I found Guacamole’s IP configurations in the two config files for each container var/lib/docker/containers/CONTAINERIDs/config.v2.json where IPs like 172.16.0.1, 172.16.0.2, 172.16.0.3 are specified. Also, in UCR I can find appcenter/apps/guacamole/ip with the value 172.16.0.0/24. I tried to change the IPs / networks at both these entries, but the bridge keeps reappering with the same network. Also, the changes in config.v2.json are reverted after reboot.

Where and how can I change Guacamole’s docker network to something outside my network?

Thanks in advance!