For anyone wondering about the specifics:

"For example, there was a dispute about whether Whatsapp uses a technology that Blackberry holds a patent on when sending a chat history to a third party via email."

(translated via Deepl, source https://t3n.de/news/gericht-verbietet-apps-whatsapp-1231364/)

The actual legal claims are in this document: http://docs.dpaq.de/13322-031127684372.pdf