WhatsApp co-founder Jan Koum is leaving the company.

A Washington Post report suggested that his departure is due to disagreements with parent company Facebook regarding how user data is shared.

Since it bought WhatsApp, Facebook has made changes to the app’s user agreement to allow some user data sharing.

WhatsApp co-founder Jan Koum is set to quit the company and leave his post as a member of Facebook’s board of directors. According to the Washington Post, the decision comes after Koum clashed with Facebook over its attempts to use WhatsApp users’ personal and “weaken its encryption.”

In a post on Facebook, Jan Koum confirmed his exit, although the post made no mention of the claims mentioned above, or a departure date. Koum said:

“It’s been almost a decade since Brian and I started WhatsApp, and it’s been an amazing journey with some of the best people. But it is time for me to move on. I’ve been blessed to work with such an incredibly small team and see how a crazy amount of focus can produce an app used by so many people all over the world.”

WhatsApp has long held the protection of user data as an important part of the app. In 2014, it began to encrypt messages sent on the platform and, in 2016, all forms of communication within the app began to be encrypted. The company has also resisted the attempts of governments in the U.S. and Brazil to hand over data belonging to its users.

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However, things were always likely to come to a head when Facebook bought the company. Data collection forms a crucial part of Facebook’s business model, as it sells data to advertisers. While the WhatsApp co-founders promised that nothing in the way it handled data would change after the takeover, in 2016, the messaging service began to share some user data with its parent company.

Brian Acton, WhatsApp’s other co-founder, left his position at the company soon after. Earlier this year, while Facebook was in the midst of the Cambridge Analytica scandal, he sent out a Tweet telling users to “#deletefacebook.”

In response to Jan Koum’s announcement on Facebook, Mark Zuckerberg left a comment saying:

“I will miss working so closely with you. I’m grateful for everything you’ve done to help connect the world, and for everything you’ve taught me, including about encryption and its ability to take power from centralized systems and put it back in people’s hands. Those values will always be at the heart of WhatsApp.”

Next up: WhatsApp co-founder says it’s time to delete Facebook.