WhatsApp, one of the most widely used chat apps in the world, still refuses to help justice in Hong Kong.
Requests from the authorities in the autonomous city for user data will not be processed for the time being.
WhatsApp, owned by Facebook, says it wants to know first how the new security law will affect human rights.
Hong Kong has been part of China since 1997, but the inhabitants of the former British colony always had far more liberties than people in the rest of the country.
For example, residents can use Google, Twitter and Facebook, which are blocked in mainland China. Such services are also used by demonstrators to keep in touch. For example, they warn each other via encrypted chat apps where the police are.
China recently passed a law that would severely punish crimes such as separatism, terrorism and collusion with foreign powers. Critics think that the legislation is intended to silence critics of the communist rulers.