Facebook is suing BlackBerry for patent infringement, according to a report from Bloomberg. The lawsuit comes just months after BlackBerry sued Facebook, alleging that the social media company and its WhatsApp and Instagram subsidiaries infringed on BlackBerry messaging app patents.

In the complaint, filed in San Francisco federal court, Facebook accuses BlackBerry of infringing on several patented processes and technologies surrounding voice messaging, how a mobile device delivers graphics, and the tracking and analysis of GPS data. In total, Facebook is asking for unspecified damages for infringement of six patents.

Back in March, BlackBerry sued Facebook, saying that the company was “using a number of the innovative security, user interface, and functionality enhancing features that made BlackBerry’s products such a critical and commercial success in the first place.” Some of the patents in question cover interface elements as broad as the displaying of message timestamps and the ability to tag friends and family in photos. BlackBerry and its BBM system rose to popularity in the mid to late-2000s, while Facebook’s Messenger spun out of the core app in 2013. By spring 2014, Facebook turned off the ability to send messages in the original app, forcing users to migrate to the standalone Messenger.