As the world left shocked at the news of a bug in WhatsApp’s audio call feature that allowed hackers to install spyware onto Android and iOS phones just by calling the target, its rival Telegram has warned that WhatsApp will continue to be open to surveillance.

Unlike Telegram, WhatsApp is not open source, so there’s no way for a security researcher to easily check whether there are backdoors in its code.

It coincided with an aggressive push for all of its users to back up their chats in the cloud.

Last year, the founders of WhatsApp left the company due to concerns over users’ privacy.

“We at Telegram have to acknowledge our responsibility in forming the future. It’s either us or the Facebook monopoly. It’s either freedom and privacy or greed and hypocrisy,” he added, stressing that an era of freedom and privacy will begin soon.