I have received a reply from B & O, unfortunately not as desired!
I think it's a shame that the remote app is not updated, it would have been a small problem to fix the iOS 12 bug!
The answer:
"Hi Erich! We are sorry for
the inconvenience. We reviewed this internally and the BeoRemote app is no
longer maintained as it has been replaced by the Bang & Olufsen app. Adding
your TV to the Bang & Olufsen app will give you similar control features as
in the BeoRemote app. Please install it and try it out."
Location: Switzerland