The new Zattoo app is available on all LG models from 2016 (webOS 3.x and newer) in Germany, Switzerland and Austria.
On models older than 2016 (webOS 2.x and older) an old Zattoo app is currently still available, but unfortunately it is no longer updated and supported.
How to update the Zattoo app on my LG TV 2016 or newer?
1. Go to Content Store on your LG TV via the Home menu.
2. Search for Zattoo.
3. Choose Update / Install update.
4. Wait few seconds until the update is finished.