Hi Klojum,
Thank you very much - renaming guisettings.xml did the trick for me.
I'm not yet familiar with Estuary and navigating it without any kind of text in the GUI wasn't very feasible.
But now I'll go on upgrading the rest of my Kodis - I have a lot. 
Best regards,
Lars
Hi there,
I just upgraded a RPi 3 running OpenELEC to LibreELEC 8.0.2. Everything apparently went smooth - the box upgraded and loaded the new release.
But: The earlier version had Danish as the chosen interface language - and Kodi came up with a new (and to me unknown) skin and no texts at all except for a few lines of text here and there in English: I guess these texts haven't been translated to Danish yet.
How do I add Danish language support to my new LibreELEC?
Beeing a long time Kodi/XBMC user and some kind of a Linux expert, I would prefer to do it using SSH, if possible: The GUI is very difficult to navigate as it has no texts at all...
Best regards,
Lars
