[Medienmogul]

The connection to my Kody system changes frequently dependent on the used network (ethernet, Wifi, Tethered AP). 

Therefore I was searching where to change the IP address Kore uses to connect to Kodi. However I wasn't able to find this settings in Kore.

Where can I change the configuration?

[syncd]

On the left sidebar, tap Kodi's instance name and you'll be taken to a list of configured media centers, where you can change them

[Medienmogul]

Thanks, that menu is very well hidden - headings usually do not provide functionality.
May be there should be an entry in the settings/preferences view to open this menu, too.