Grindr, the world’s biggest LGBT+ dating app, is facing a mass data protection lawsuit from 670 users who say that their personal information – including their HIV status – was shared with third-party advertisers. The lawsuit was filed on Monday in London’s High Court by the law firm Austen Hayes and alleges the information was disseminated via “covert tracking technology”, in breach of UK privacy laws. Thousands of users are allegedly affected and many more may join the case. Grindr said it would stop sharing users’ HIV status with third parties in 2018, after it emerged that the app had been providing data to the advertisers Apptimize and Localytics. This new lawsuit alleges that personal information was shared as late as 2020. Grindr says it will “respond vigorously” to the claim, which “appears to be based on a mischaracterisation of practices from more than four years ago”.