WhatsApp Inc, the California-based mobile app developer with upwards of 400 million users, was subject to a joint investigation by Dutch and Canadian Privacy Authorities for violations of their national privacy and data protection laws, reports Bird & Bird.

On the basis of the results of their investigation, the two data protection authorities concluded that WhatsApp was violating ‘certain internationally accepted privacy principles’, particularly in relation to the retention and disclosure of the users’ personal data.

Only iPhone users running iOS 6 on their devices have the option of adding contacts manually rather than uploading the mobile address numbers of their address books to company servers automatically. The authorities deem this not acceptable, as they hold that both users and non-users should have control over their personal data: users must be able to freely decide what contact details they wish to share with WhatsApp.