Loosing ipv4 default routes on hetzner cloud

[nixmomo]

Hi, i have some trouble with the config of zevenet.
First issue, i need to add the default gateway and routes after a reboot. Zevenet is deleting the whole config in interfaces.

Also ipv6 is not working for me because zevenet is deleting / overwriting the interfaces file.

Via Webgui it is not possible to add a ipv6 address (or i have not found it?)

So how can i keep the routings persistent and how can i add a static ipv6 and his gateway?

I would write it into /etc/network/interfaces but thats overwritten after every restart.