https://techcrunch.com/2019/02/27/blackberry-sues-twitter-for-patent-infringement/

BlackBerry, the former smartphone maker, is suing Twitter for alleged patent infringement. If this sounds familiar, it may be because BlackBerry filed a patent infringement suit against Facebook last year.

In its complaint, BlackBerry alleges Twitter has infringed and continues to infringe on six of its patents, which cover things like push notifications, silencing notifications for a message thread and mobile advertising techniques.